TH400 Amateur Build
- Thread starter TXChevy
- Start date
Thank you!I hope it exceeds your expectations and you find ZERO issues!
I appreciate that.
I've thought about a R&P steering setup, but I'm using the stock setup.So I bet your already thinking about an IRS with a Corvette rear or maybe a Jag!!!
Hopefully you do more than start it up, like maybe drive it!
I'm really ready to drive it after such a long time. Everything is done except for the drag link and tie rods which I've already started on. Using whats called "poor man's power steering" on these tri-fives, which is a bearing assembly vs bushing on the idler arm. Pretty effective.
First Test Start-up .....
Well my friends, unfortunately today was a complete fail......
Everything connected, initial 4 qts in the unit, then start-up while more fluid added immediately. This is as-per fresh start instructions.
I'm so glad I decided to install a line pressure gauge, I think it saved a complete disaster.
Engine running just slightly above idle, about 850 rpm or so.
ZERO line pressure, ran for 30 seconds or so then shut it down. No weird noises or anything, just no pressure.
Repeat for another 30 seconds same result. Converter had been filled and pump had been primed with trans lube - some level of pressure should have shown right away.
Repeat for another 30 seconds, same result.
Repeat again with attempt to put it in reverse, which uses all the clutch packs, has the most fluid fill needed and has the highest line pressure.
Engine died, telling me that the unit was doing nothing.
I reached out to my friend Nick at Nick's Transmissions - he said on a fresh build initial zero pressure can be from very low fluid but we had a total of 10 qts in it. He's thinking an issue with the pump, possibly the booster/pressure relief valve (I used a Sonnax upgraded booster valve) or pump itself.
If you recall we had the issue with the converter hub not fitting into the crank, I had it turned down .0025 in a machine lathe which took care of that. Currently, unbolted from the flexplate it turns smooth as butter, no burrs or strange noises. When we first tried bolting the transmission in, we ran into a lot of resistance so we stopped. However, there was enough pressure on the converter that the hub got slightly "compressed" before we realized a problem and stopped. I've wondered if this pressure was transmitted to the pump gears and caused an issue.
You can see the mark on the hub where it was pushed into the smaller diameter crank pilot.
I think that translates to a lot of force back onto the pump.
As mentioned the current (cleaned up) re-worked hub fits perfectly, and I'm 1000% certain that the converter is correctly installed.
Following some more logic, if I had messed up seals or clutch packs, the issue would not be a lack of pressure, it would be a problem going into gear or shifting. Just like on an engine, if you have zero oil pressure and the gauge is good, pickup tube is attached, better check that pump.
I cracked a cooler line fitting loose (engine off) and there was just a dribble of fluid, nothing like what you'd expect. I also swapped in another pressure gauge with the same result and just a dribble from the line pressure hose.
We drained a total of 5 qts out of the 10 we added and examined the fluid.
General appearance and smell was like new as you'd expect. No clutch debris.
However, there was some metallic debris.
You can see some glitter here.
Nothing really in the pan.
I would expect a bit of break-in material - what you see is from 2 minutes of run time with zero pressure so I'm looking at the pump.
Filter is solidly in place. Drips and drabs like you'd expect when you drop the pan.
Pickup tube is also fully seated, with 2 o-rings in the case end.
So there you have it.
Very discouraging, but I've got time and money invested here so I need to resolve the problem.
We're going to pull it back out next week and start with the pump. I'll have it back on my super-duper fixture holder so I'll be able to get into as deeply as needed. But as mentioned, right now the start will be to take the pump apart, inspect the gears and verify that the booster valve is installed correctly. If there's even a remote question on the pump I'm replacing it.
On the plus side, we've gotten pretty good at transmission remove/install and I won't need to do all that mount, cooler line, etc etc stuff again.
I go see about my back surgery date tomorrow so looks like next week may be it for this car until recovery/rehab. But rest assured I'll follow up next week and whenever this thing goes back together again.
I keep repeating "it's just a hobby".......
Well my friends, unfortunately today was a complete fail......
Everything connected, initial 4 qts in the unit, then start-up while more fluid added immediately. This is as-per fresh start instructions.
I'm so glad I decided to install a line pressure gauge, I think it saved a complete disaster.
Engine running just slightly above idle, about 850 rpm or so.
ZERO line pressure, ran for 30 seconds or so then shut it down. No weird noises or anything, just no pressure.
Repeat for another 30 seconds same result. Converter had been filled and pump had been primed with trans lube - some level of pressure should have shown right away.
Repeat for another 30 seconds, same result.
Repeat again with attempt to put it in reverse, which uses all the clutch packs, has the most fluid fill needed and has the highest line pressure.
Engine died, telling me that the unit was doing nothing.
I reached out to my friend Nick at Nick's Transmissions - he said on a fresh build initial zero pressure can be from very low fluid but we had a total of 10 qts in it. He's thinking an issue with the pump, possibly the booster/pressure relief valve (I used a Sonnax upgraded booster valve) or pump itself.
If you recall we had the issue with the converter hub not fitting into the crank, I had it turned down .0025 in a machine lathe which took care of that. Currently, unbolted from the flexplate it turns smooth as butter, no burrs or strange noises. When we first tried bolting the transmission in, we ran into a lot of resistance so we stopped. However, there was enough pressure on the converter that the hub got slightly "compressed" before we realized a problem and stopped. I've wondered if this pressure was transmitted to the pump gears and caused an issue.
You can see the mark on the hub where it was pushed into the smaller diameter crank pilot.
I think that translates to a lot of force back onto the pump.
As mentioned the current (cleaned up) re-worked hub fits perfectly, and I'm 1000% certain that the converter is correctly installed.
Following some more logic, if I had messed up seals or clutch packs, the issue would not be a lack of pressure, it would be a problem going into gear or shifting. Just like on an engine, if you have zero oil pressure and the gauge is good, pickup tube is attached, better check that pump.
I cracked a cooler line fitting loose (engine off) and there was just a dribble of fluid, nothing like what you'd expect. I also swapped in another pressure gauge with the same result and just a dribble from the line pressure hose.
We drained a total of 5 qts out of the 10 we added and examined the fluid.
General appearance and smell was like new as you'd expect. No clutch debris.
However, there was some metallic debris.
You can see some glitter here.
Nothing really in the pan.
I would expect a bit of break-in material - what you see is from 2 minutes of run time with zero pressure so I'm looking at the pump.
Filter is solidly in place. Drips and drabs like you'd expect when you drop the pan.
Pickup tube is also fully seated, with 2 o-rings in the case end.
So there you have it.
Very discouraging, but I've got time and money invested here so I need to resolve the problem.
We're going to pull it back out next week and start with the pump. I'll have it back on my super-duper fixture holder so I'll be able to get into as deeply as needed. But as mentioned, right now the start will be to take the pump apart, inspect the gears and verify that the booster valve is installed correctly. If there's even a remote question on the pump I'm replacing it.
On the plus side, we've gotten pretty good at transmission remove/install and I won't need to do all that mount, cooler line, etc etc stuff again.
I go see about my back surgery date tomorrow so looks like next week may be it for this car until recovery/rehab. But rest assured I'll follow up next week and whenever this thing goes back together again.
I keep repeating "it's just a hobby".......
now this may seem to be a really silly question
but humor me a bit , there's not a single person in this hobby (yes I'm certainly in that group)
that's never made several mistakes ,thats how most of us learn,
its part of paying your dues! as the saying goes!!
(humor the old guy I had some inventively (and at times entertainingly) ignorant friends in the past
Ive seen clutch discs installed backwards, throw out bearings installed wrong, shifter forks not adjusted, manual shifter not bolted to the trans tail shaft bracket,
guys trying to install a 11" disc on a 10.4" pressure plate, and no trans filter installed, and a bunch of other issues
)https://garage.grumpysperformance.c...e-dry-rebuild-transmission.17954/#post-112672
(but trust me Ive seen it not being done correctly before now, on a trans install)
you verified the torque converters fully and correctly seated in the transmission, that the flex plates correctly bolted to the crank and the flex plates facing the right direction and is correctly bolted to the torque converter?
people tend to skip over the simple things at times, and assume its something complicated and expensive to fix
(it may be but check/ fix the simple stuff first)
make a check list of everything that could be wrong and start checking off the list as you verify each issue
personally I'm impressed with what youve done so far!
its a learning process, and I know I could not rebuild an auto trans flawlessly on the first attempt
ive build about 200 plus engines, over the last 60 plus years, and I'M still learning new tricks,
acquiring new tools , I originally never knew I needed,
and think back on a dozen minor and a few majors screw -ups on the first couple engine builds
having knowledgeable mentors, asking questions on damn near everything,
and doing research is certainly helpful
KEEP IN MIND!
if your not getting in WAY over your head in projects,
and being forced to learn new skills,
and acquire new tools, your just not learning anything new
but humor me a bit , there's not a single person in this hobby (yes I'm certainly in that group)
that's never made several mistakes ,thats how most of us learn,
its part of paying your dues! as the saying goes!!
(humor the old guy I had some inventively (and at times entertainingly) ignorant friends in the past
Ive seen clutch discs installed backwards, throw out bearings installed wrong, shifter forks not adjusted, manual shifter not bolted to the trans tail shaft bracket,
guys trying to install a 11" disc on a 10.4" pressure plate, and no trans filter installed, and a bunch of other issues
)https://garage.grumpysperformance.c...e-dry-rebuild-transmission.17954/#post-112672
(but trust me Ive seen it not being done correctly before now, on a trans install)
you verified the torque converters fully and correctly seated in the transmission, that the flex plates correctly bolted to the crank and the flex plates facing the right direction and is correctly bolted to the torque converter?
people tend to skip over the simple things at times, and assume its something complicated and expensive to fix
(it may be but check/ fix the simple stuff first)
make a check list of everything that could be wrong and start checking off the list as you verify each issue
personally I'm impressed with what youve done so far!
its a learning process, and I know I could not rebuild an auto trans flawlessly on the first attempt
ive build about 200 plus engines, over the last 60 plus years, and I'M still learning new tricks,
acquiring new tools , I originally never knew I needed,
and think back on a dozen minor and a few majors screw -ups on the first couple engine builds
having knowledgeable mentors, asking questions on damn near everything,
and doing research is certainly helpful
KEEP IN MIND!
if your not getting in WAY over your head in projects,
and being forced to learn new skills,
and acquire new tools, your just not learning anything new
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Good questions to ask!
Yes I can say with certainty that the flexplate is installed correctly, fully seated and that the converter was also fully seated. I pulled it out by hand slightly to get to 1/8" of the flexplate. If it was jammed on the gears I couldn't have done that. Right now its unbolted from the flexplate and it spins beautifully by hand.
I'm looking at the problem as to why there is zero pressure - why is the pump unable to produce pressure? So this diagnosis looks first at this and not so much as to what's further inside the unit.
Edit - I'm also going to verify that the pick-up tube itself isn't cracked. Even a hairline crack can cause the no pressure condition.
Even if something was wrong further inside, I should still see some sort of line pressure in Park. In that position only the rear band is applied, none of the other clutch packs, front band, low roller clutch or sprag. Logically this points to the pump, or a pump component, like the PR valve. So that's my initial start point.
I'll say it again though - that cheapo pressure gauge may have saved this transmission from self destruction if we had kept running it without knowing there wasn't any line pressure. My hope is that - if indeed its the pump - damage is limited to that component.
Yes I can say with certainty that the flexplate is installed correctly, fully seated and that the converter was also fully seated. I pulled it out by hand slightly to get to 1/8" of the flexplate. If it was jammed on the gears I couldn't have done that. Right now its unbolted from the flexplate and it spins beautifully by hand.
I'm looking at the problem as to why there is zero pressure - why is the pump unable to produce pressure? So this diagnosis looks first at this and not so much as to what's further inside the unit.
Edit - I'm also going to verify that the pick-up tube itself isn't cracked. Even a hairline crack can cause the no pressure condition.
Even if something was wrong further inside, I should still see some sort of line pressure in Park. In that position only the rear band is applied, none of the other clutch packs, front band, low roller clutch or sprag. Logically this points to the pump, or a pump component, like the PR valve. So that's my initial start point.
I'll say it again though - that cheapo pressure gauge may have saved this transmission from self destruction if we had kept running it without knowing there wasn't any line pressure. My hope is that - if indeed its the pump - damage is limited to that component.
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I've got everything prepped, ready to pull it out in the morning. Also took the opportunity to touch up the headers and exhaust where they got scraped up a bit.
That's a "scrape plate" with 2 water drain holes welded to the header. In case the header scrapes on something it will damage the plate instead of the header.
Great coating. I've been happy with it.
And I saved the header gaskets, they're very good but not cheap.
Full .125 thickness- they seal great, especially with the beaded weld style flanged headers I have. You can see the compression at the weld bead, with plenty of gasket thickness left.
Remflex #2036, 1.75 round port exhaust gaskets.
So yes, I'm hoping for a simple fix. I have to pull the pump to verify the condition of the gears and I'll check the PR valve, pickup tube etc.
I don't want to have tunnel vision, but the zero pressure points to pump not working or unable to pull fluid. Even if I had messed up clutch packs, valve body, etc l, I would still expect to see line pressure in park.
One benefit of this thread and the 600+ pictures I took during the entire rebuild is that I can verify what I did at each step.
That's a "scrape plate" with 2 water drain holes welded to the header. In case the header scrapes on something it will damage the plate instead of the header.
Great coating. I've been happy with it.
And I saved the header gaskets, they're very good but not cheap.
Full .125 thickness- they seal great, especially with the beaded weld style flanged headers I have. You can see the compression at the weld bead, with plenty of gasket thickness left.
Remflex #2036, 1.75 round port exhaust gaskets.
So yes, I'm hoping for a simple fix. I have to pull the pump to verify the condition of the gears and I'll check the PR valve, pickup tube etc.
I don't want to have tunnel vision, but the zero pressure points to pump not working or unable to pull fluid. Even if I had messed up clutch packs, valve body, etc l, I would still expect to see line pressure in park.
One benefit of this thread and the 600+ pictures I took during the entire rebuild is that I can verify what I did at each step.
Well, the Transmission is out. I pulled the pump and opened it up.
Observations:
1. Zero debris in pump
2. Gears look identical to pics when I checked the pump.
3. Converter was fully seated, hub and gear tangs look perfect.
4. Pump gasket orientation was correct.
5. Remaining fluid as it drains looks good.
6. Looking down into the unit, looks clean.
7. Pickup tube was installed correctly, snug fit with 2 o-rings, good fit into filter.
8. Pickup tube air-checked for hairline crack, found nothing.
I had installed the Sonnax boost PR valve. I've not yet removed it to verify correct installation but my pictures show correct parts sequence. I'll remove it and inspect vs the original valve I had kept.
If there's a problem with that boost valve, can that result in zero pressure? I keep thinking that even if a valve body valve or seal etc somewhere was messed up, the pump would still show pressure.
I think also that worn pump gears should still show some (low) pressure. This pump worked ok before rebuild so I've done something.
I was hoping for a smoking gun, no such luck.
Observations:
1. Zero debris in pump
2. Gears look identical to pics when I checked the pump.
3. Converter was fully seated, hub and gear tangs look perfect.
4. Pump gasket orientation was correct.
5. Remaining fluid as it drains looks good.
6. Looking down into the unit, looks clean.
7. Pickup tube was installed correctly, snug fit with 2 o-rings, good fit into filter.
8. Pickup tube air-checked for hairline crack, found nothing.
I had installed the Sonnax boost PR valve. I've not yet removed it to verify correct installation but my pictures show correct parts sequence. I'll remove it and inspect vs the original valve I had kept.
If there's a problem with that boost valve, can that result in zero pressure? I keep thinking that even if a valve body valve or seal etc somewhere was messed up, the pump would still show pressure.
I think also that worn pump gears should still show some (low) pressure. This pump worked ok before rebuild so I've done something.
I was hoping for a smoking gun, no such luck.
Yes, I always fear that when I have to go back and remove something that's very time consuming I FIND NOTHING, now what!!!
So very frustrating, but you are taking it alot better than I would!
Long shot, but is the passage to the port where you are measuring pressure plugged internally?
Crack in the case?
Internal bleeding? Left out a seal somewhere?
Can you test the pump outside the trans? Make a plate with holes in the right place and thread them for your pressure gauge?
Before you reinstall the trans, can you test it for pressure while it's still in the holding fixture. Can you drive the pump with pan installed and full of fluid to see if you can measure pressure before installing it in the car again???
Will it push fluid out the pressure port while it's operating?
.
So very frustrating, but you are taking it alot better than I would!
Long shot, but is the passage to the port where you are measuring pressure plugged internally?
Crack in the case?
Internal bleeding? Left out a seal somewhere?
Can you test the pump outside the trans? Make a plate with holes in the right place and thread them for your pressure gauge?
Before you reinstall the trans, can you test it for pressure while it's still in the holding fixture. Can you drive the pump with pan installed and full of fluid to see if you can measure pressure before installing it in the car again???
Will it push fluid out the pressure port while it's operating?
.
I'll try to figure out a way to see if I can check the assembled pump somehow. I will check the gear clearances again too just to not assume anything.
That's a good idea to see if the pump pushes anything out if that pressure port.
I did blow compressed air during assembly through all passages, including the pressure port. Clutches were air checked with 20 psi to not blow the seals. I was going to check that pressure port again but need to use moderate air pressure.
As far as internal bleed somewhere, I'd still expect to see even low pressure at the port. But I want to verify the passage route from pump to pressure port, I think its fairly direct.
I'll probably remove the valve body to verify all valves are correctly installed, but I've not yet seen any assembly pics that are questionable. I'll first look at the pressure port.
What bothers me is that when I tried to shift to reverse the engine stalled. It's a good running engine, but a bit cold natured and it had only run a minute or so before I tried shifting. Did I over-react and assume the zero line pressure was the cause rather than a good old fashioned cold stall?
Worth thinking more about:
One thing I did notice was that there was fluid inside the unit and the cooler lines dribbled a bit when disconnected. Converter was pre-filled but I think it had a bit more fluid in it. I had drained the pan when it was still in the car - when I put it on the stand and tilted it upright a couple more quarts came out.
So that tells me that somehow, some amount of fluid had to have been pumped, even at a few psi. If the pump wasn't working there wouldn't be any fluid anywhere. With this in mind I'm really looking to verify the pressure port is functional. I did check the gauge hose for obstruction, nothing.
That's a good idea to see if the pump pushes anything out if that pressure port.
I did blow compressed air during assembly through all passages, including the pressure port. Clutches were air checked with 20 psi to not blow the seals. I was going to check that pressure port again but need to use moderate air pressure.
As far as internal bleed somewhere, I'd still expect to see even low pressure at the port. But I want to verify the passage route from pump to pressure port, I think its fairly direct.
I'll probably remove the valve body to verify all valves are correctly installed, but I've not yet seen any assembly pics that are questionable. I'll first look at the pressure port.
What bothers me is that when I tried to shift to reverse the engine stalled. It's a good running engine, but a bit cold natured and it had only run a minute or so before I tried shifting. Did I over-react and assume the zero line pressure was the cause rather than a good old fashioned cold stall?
Worth thinking more about:
One thing I did notice was that there was fluid inside the unit and the cooler lines dribbled a bit when disconnected. Converter was pre-filled but I think it had a bit more fluid in it. I had drained the pan when it was still in the car - when I put it on the stand and tilted it upright a couple more quarts came out.
So that tells me that somehow, some amount of fluid had to have been pumped, even at a few psi. If the pump wasn't working there wouldn't be any fluid anywhere. With this in mind I'm really looking to verify the pressure port is functional. I did check the gauge hose for obstruction, nothing.
Without fluid pressure would the trans go into gear and lockup the clutches, therefore killing the engine?
I do think that maybe you over reacted, but I also think you are more cautious than myself. I'm a little more of a risk taker. You certainly can't go wrong by stopping to check out the perceived problem.
I will be interested to see what you find with the Sonnax upgraded booster valve.
.
No, without fluid pressure the clutch packs can't activate. Now that I think about it, the transmission wouldn't do anything, as if there was low fluid. It doesn't seem logical that the transmission would kill the engine if there wasn't any fluid pressure to activate clutches.
Yes I'm the first one to say I'm sometimes too cautious!
I've looked further......
1. The pump gear thickness is to spec, and there's not excessive gap from top of gear to pump body.
2. There's some slight scoring at the outer wall where the larger pump gear is located. The book says if any scoring can be felt with a fingernail, repair or replace the pump body. I'll get back to this. As mentioned, the gears and the faces of the pump body and stator look great. The pump body is not warped.
3. I removed the valve body and re checked the gaskets - they are correct and the valve body was torqued correctly.
4. I ran 20 psi air into the pressure port and it came right out at the pump ports in the case. So there's no obstruction.
5. There's actually 2 pump ports that I can get air out of when I start at the pressure port. With transmission in neutral and my fingers blocking the 2 ports, I got fluid out of end of the manual valve which would go into the pan. Not sure about this one, I'm trying to find a hydraulic circuit diagram for a th400.
6. The separator plate at the valve body is the same B&M plate that's been in there forever, so I don't see that as an issue. But I'll get back to this too.
7. The Sonnax booster/PR valve was installed correctly.
8. There is fluid everywhere within the transmission, as you would expect in a unit you just removed. As mentioned, we drained about 4 or 5 qts, and a couple more drained out the back when I inverted it. The cooler lines had some fluid, I'm not sure if that was less than usual or not. The valve body had fluid in the passages, so again, the only way that all that fluid could get ANYWHERE would be to be pumped.
Back to #2, #5 and #6 .....
As far as I can tell the unit has been rebuilt correctly - that's not trying to make myself look good, it's just what I'm finding. I'm not moving further into the unit because the drivetrain is dead without fluid. So taking it all out doesn't address the pressure issue.
#2. I'm not one to fire the parts cannon, but I'm leaning towards getting another pump. All the info that I see is very clear on the very tight tolerances at the pump gears. At the same time, I realized that if I'm using any sort of pressure increase spring, I really should install a converter feed restrictor. Pretty easy. I've not found anybody that doesn't do this with any sort of performance rebuild.
#5. I can't say that seeing fluid out of the manual valve in neutral is wrong - I just need to verify if this is some sort of bypass when the unit is in neutral and the engine is running.
#6. Since this separator plate was used before, there's no reason it suddenly would not be correct. It has a couple of restriction to the modulator valve, but again, this isn't anything I've suddenly changed.
Today's conclusion:
I'm going to replace the pump. I simply cannot find anything wrong with this rebuild. There's a very direct passage pump-to-pressure port and if I'm not seeing any hint of pressure that still points to the pump again. I looked around and I may get a pump from ATI, same as my converter, that also includes the booster/PR valve.
If the converter was bad, it would show up when driving, not in Park. The pump charges (fills) the converter, and the converter attachment is direct to the pump. It bolts to the flexplate and the welded hub turns the pump gears. So again, the path seems to lead to the pump.
I took 600+ pictures of this entire build, from teardown "before" pics and as I was working on each component. I've been going over them very carefully and still haven't found anything questionable.
When we try again, I'm going to keep the engine going for more than 30 seconds at a time and I'll make sure to watch for a stall putting it into gear. That certainly may have been an over-reaction.
Rick, I appreciate yours and anyone's feedback and suggestions. I know at this point this is getting pretty tedious to the casual reader, but not all installs go smoothly. I'm approaching this in my own way, trying to be methodical, so I appreciate the patience of those reading through all this.
Yes I'm the first one to say I'm sometimes too cautious!
I've looked further......
1. The pump gear thickness is to spec, and there's not excessive gap from top of gear to pump body.
2. There's some slight scoring at the outer wall where the larger pump gear is located. The book says if any scoring can be felt with a fingernail, repair or replace the pump body. I'll get back to this. As mentioned, the gears and the faces of the pump body and stator look great. The pump body is not warped.
3. I removed the valve body and re checked the gaskets - they are correct and the valve body was torqued correctly.
4. I ran 20 psi air into the pressure port and it came right out at the pump ports in the case. So there's no obstruction.
5. There's actually 2 pump ports that I can get air out of when I start at the pressure port. With transmission in neutral and my fingers blocking the 2 ports, I got fluid out of end of the manual valve which would go into the pan. Not sure about this one, I'm trying to find a hydraulic circuit diagram for a th400.
6. The separator plate at the valve body is the same B&M plate that's been in there forever, so I don't see that as an issue. But I'll get back to this too.
7. The Sonnax booster/PR valve was installed correctly.
8. There is fluid everywhere within the transmission, as you would expect in a unit you just removed. As mentioned, we drained about 4 or 5 qts, and a couple more drained out the back when I inverted it. The cooler lines had some fluid, I'm not sure if that was less than usual or not. The valve body had fluid in the passages, so again, the only way that all that fluid could get ANYWHERE would be to be pumped.
Back to #2, #5 and #6 .....
As far as I can tell the unit has been rebuilt correctly - that's not trying to make myself look good, it's just what I'm finding. I'm not moving further into the unit because the drivetrain is dead without fluid. So taking it all out doesn't address the pressure issue.
#2. I'm not one to fire the parts cannon, but I'm leaning towards getting another pump. All the info that I see is very clear on the very tight tolerances at the pump gears. At the same time, I realized that if I'm using any sort of pressure increase spring, I really should install a converter feed restrictor. Pretty easy. I've not found anybody that doesn't do this with any sort of performance rebuild.
#5. I can't say that seeing fluid out of the manual valve in neutral is wrong - I just need to verify if this is some sort of bypass when the unit is in neutral and the engine is running.
#6. Since this separator plate was used before, there's no reason it suddenly would not be correct. It has a couple of restriction to the modulator valve, but again, this isn't anything I've suddenly changed.
Today's conclusion:
I'm going to replace the pump. I simply cannot find anything wrong with this rebuild. There's a very direct passage pump-to-pressure port and if I'm not seeing any hint of pressure that still points to the pump again. I looked around and I may get a pump from ATI, same as my converter, that also includes the booster/PR valve.
If the converter was bad, it would show up when driving, not in Park. The pump charges (fills) the converter, and the converter attachment is direct to the pump. It bolts to the flexplate and the welded hub turns the pump gears. So again, the path seems to lead to the pump.
I took 600+ pictures of this entire build, from teardown "before" pics and as I was working on each component. I've been going over them very carefully and still haven't found anything questionable.
When we try again, I'm going to keep the engine going for more than 30 seconds at a time and I'll make sure to watch for a stall putting it into gear. That certainly may have been an over-reaction.
Rick, I appreciate yours and anyone's feedback and suggestions. I know at this point this is getting pretty tedious to the casual reader, but not all installs go smoothly. I'm approaching this in my own way, trying to be methodical, so I appreciate the patience of those reading through all this.
just a silly question,
now I fully admit I have limited skills in the auto transmission rebuilding skill sets,
but I tried following your rebuild and it looked like you did a decent job... so,
I ask myself.... how many quarts of trans fluid did you use ,
I called a friend I know that works in an Orlando/ FLA, chevy dealership, he says 11 quarts in his TH-400
(1970 454 Chevelle)
I know he has a larger aftermarket radiator, but I doubt that changed the trans fluid capacity much)
this chart says you need 6 quarts in the trans and 3-4 more in the stall converter
I think that means it requires 9-10 quarts in the transmission minimum to start and run.
(plus maybe 1-2 quarts in the trans fluid cooler, ( is that 11-12 quarts ? total with fluid)
in the radiator and lines or in a separate fluid cooler,??)
is that 10-11 quarts) did you check the trans fluid dip stick fluid level with the engine idling in neutral/or park?
now I fully admit I have limited skills in the auto transmission rebuilding skill sets,
but I tried following your rebuild and it looked like you did a decent job... so,
I ask myself.... how many quarts of trans fluid did you use ,
I called a friend I know that works in an Orlando/ FLA, chevy dealership, he says 11 quarts in his TH-400
(1970 454 Chevelle)
I know he has a larger aftermarket radiator, but I doubt that changed the trans fluid capacity much)
this chart says you need 6 quarts in the trans and 3-4 more in the stall converter
(plus maybe 1-2 quarts in the trans fluid cooler, ( is that 11-12 quarts ? total with fluid)
in the radiator and lines or in a separate fluid cooler,??)
is that 10-11 quarts) did you check the trans fluid dip stick fluid level with the engine idling in neutral/or park?
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Grumpy, that's a good question and thanks for asking your friend.
Before installing, I put fluid in converter. We put in 4 qts fluid in before starting.
Immediately at starting we added 4 more qts. Then between all the starts and stops we added about 3 more qts.
Spec with deep pan and large cooler is 10-12 qts so there should have been enough fluid in it to show at least some pressure.
It checked full with engine off - I know that the level will go down when running since the converter gets filled. And that you check fluid with fluid to temp, in park, engine running.
Edit - after I wrote the above post, I got to thinking about the gearset in the pump.
Back on page 2, I had made a comment about the orientation of each gearset.
The inner gear only goes in one way due to the tangs for the converter hub.
The left side here is the "up" side as it lays into the pump. Note there is no chamfer.
Left side here is the "down" side of the gear, note a slight chamfer on the gears.
There's a video that mentions the chamfer on the gearsets to face down if you don't remember which way they were when you pulled the pump apart. Of course, the best installation is to make note of the gearsets before you remove them.
I had commented that the ATSG manual says to put the gearsets with any markings facing up, so I was trying to sort out what was correct.
Among the pictures I took I found solid info on what the gearset orientation was per their original factory installation.
You'll notice that there's no marking on the outer gear.
This is how I installed the gearset. Note the mark on the outer gear.
I'm not saying this was the issue, I'm pointing out a discrepancy in my installation.
Thinking about the extremely tight tolerances in the pump, this may be a factor, right now I don't know, but it's worth noting.
On the outer gear you can see a significant chamfer in the edge of the gear.
Left side would be the original "down" side of the gear.
You can see the difference in a much smaller chamfer on the original "up" side of the gear.
I know it looks like a small difference but there MUST be a reason why the machining is different on each side of the gears.
If it didn't matter, then both sides would be the same.
The pocket itself has a slight groove in the base, running along the perimeter. So between this groove and the gearset chamfer, there's a small channel of sorts. What the dynamics of this may be, I have no idea. But again, there must be a reason.
So even though I don't know the particular reasons for specific gear orientation, I do know that I didn't reinstall the outer gear as it came from the factory. What impact that may have had, I don't know that either, but at least I found something.
Before installing, I put fluid in converter. We put in 4 qts fluid in before starting.
Immediately at starting we added 4 more qts. Then between all the starts and stops we added about 3 more qts.
Spec with deep pan and large cooler is 10-12 qts so there should have been enough fluid in it to show at least some pressure.
It checked full with engine off - I know that the level will go down when running since the converter gets filled. And that you check fluid with fluid to temp, in park, engine running.
Edit - after I wrote the above post, I got to thinking about the gearset in the pump.
Back on page 2, I had made a comment about the orientation of each gearset.
The inner gear only goes in one way due to the tangs for the converter hub.
The left side here is the "up" side as it lays into the pump. Note there is no chamfer.
Left side here is the "down" side of the gear, note a slight chamfer on the gears.
There's a video that mentions the chamfer on the gearsets to face down if you don't remember which way they were when you pulled the pump apart. Of course, the best installation is to make note of the gearsets before you remove them.
I had commented that the ATSG manual says to put the gearsets with any markings facing up, so I was trying to sort out what was correct.
Among the pictures I took I found solid info on what the gearset orientation was per their original factory installation.
You'll notice that there's no marking on the outer gear.
This is how I installed the gearset. Note the mark on the outer gear.
I'm not saying this was the issue, I'm pointing out a discrepancy in my installation.
Thinking about the extremely tight tolerances in the pump, this may be a factor, right now I don't know, but it's worth noting.
On the outer gear you can see a significant chamfer in the edge of the gear.
Left side would be the original "down" side of the gear.
You can see the difference in a much smaller chamfer on the original "up" side of the gear.
I know it looks like a small difference but there MUST be a reason why the machining is different on each side of the gears.
If it didn't matter, then both sides would be the same.
The pocket itself has a slight groove in the base, running along the perimeter. So between this groove and the gearset chamfer, there's a small channel of sorts. What the dynamics of this may be, I have no idea. But again, there must be a reason.
So even though I don't know the particular reasons for specific gear orientation, I do know that I didn't reinstall the outer gear as it came from the factory. What impact that may have had, I don't know that either, but at least I found something.
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Thunderbolt
Well-Known Member
Could a blocked cooler line make the pump not build pressure?