Dear All,
When I first bought my ride it had an anemic 6-banger in it mated to a THM-350. It did not take long before I found a suitable SBC400 and, from there, power kept on growing (HP/TQ > 600). The THM-350 did an adequate job for a long while but soon I wanted the comfort of an overdrive trans.
I started reading about the options out there and discovered the much-neglected THM200-4R. It was used in many a luxo-barge, but also has a pedigree as it was used in the Turbo Buick! In fact the transmission-talk forum on http://www.turbobuick.com was a great source of information for me.
The 200-4R has several advantages:
- Near direct bolt in for a THM-350. No need to trim the driveshaft;
- An overdrive trans. (Of course);
- A deeper first gear than the THM-350;
- A good RPM drop from 1 – 2 (contrary to the 700-4R that has a deeper 1st gear but large RPM drop.)
- Can be built to sustain quite a bit of HP and TQ;
- Has a lockup converter.
Still, to handle over 700HHP/TQ I have roughly $2500 worth of parts in there. Over the years, I also had the trans in and out of the car 8 times… as I learned!
You do NOT need to drop as much as $2500 to bring your THM200-4R up to snuff providing yer not making significant power – say anything under 450HP/TQ.
Do the job right and you will only need to put your trans in there once and worst case scenario twice.
You CAN do this. I had NO prior trans experience and did this all in my basement and on my back in a driveway - alone.
Here’s my advice on doing this:
- Be meticulous, bag, tag and label everything as you disassemble
- Take breaks, especially when things get stubborn.
- Always check everything twice. If a snag develops, you can rule out everything you have 100% confidence in.
- Do ALL the compressed air tests. You can check all your hydraulic circuits before you ever mount the trans in the car. Same idea: if you hit a snag, it might be the Valve Body and that doesn’t require dropping the trans.
- Get the ATSG (automatic transmission service guide) and get the Video. You need both.
- Get a trashed 200-4R for parts. Interchanging the steels of the clutch packs will get your clearances spot on. And you need that!
- Get yourself a pressure gauge for testing 0 - 300 PSI
Other than assorted snapring pliers and inch/lbs + foot/lbs torque wrenches, I did not need any exotic J-tools. If you don’t have compressed air, get the tests done at a buddy’s place. They are easy to do. NOTE: having J-tools would make it much easier!
SLIDESHOW:
http://s223.photobucket.com/albums/dd204/irabel457/Trans Work/?albumview=slideshow
The job was intimidating at first. I had NO prior experience with trans work and I did the rebuild in my basement - I dont have a garage. Now, I have come to the point where working on my trans feels familiar. (I still hate Dexron three in my hair. Yes, I do all this alone, on my back on a European cobblestone drive way. Free tip: collect disposable shower caps from hotels.)
Right, what have in this trans:
- D5 locking torque converter from a Turbo Buick (your converter needs to fit your app – stock might be fine.)
- Hardened stator support. It’s the splined shaft sticking out of the pump. Originals were soft steel and often got munched. A MUST for every rebuild.
- The pump can be stock but needs chrome moly rings to guide the vanes as the stock steel can break.
- An aftermarket pressure regulator installed in the pump. Pressure rises faster and higher.
- An extra wide band: extra clamping force on the drum, a huuuuge servo and adjustable pin + hardened anchor to clamp that band.
- I modified my stock input shaft
- Rollerized center supports
- OD planetary carrier (I broke this one racing… a prosche!)
- OD planetary (This broke with it)
- Forward drum (known to break on hi power apps)
- Bottom feeder sump and deep pan. Prevents sucking air and pressure loss on hard acceleration
- Shift kit. A must if yer making any power.
- A 3 clutch 4th gear. I trimmed my own piston on a lathe and added a clutch. All blueprinted!
All my parts come from http://www.ptsxtreme.com/ Bruce, is the most knowledgeable person on the PLANET when it comes to 200-4Rs. He won't let you down. Period.
Our Lady of Blessed Speed Don't Fail Me Now!
D
PS - you'll need to get the best oil cooler you can as well!
When I first bought my ride it had an anemic 6-banger in it mated to a THM-350. It did not take long before I found a suitable SBC400 and, from there, power kept on growing (HP/TQ > 600). The THM-350 did an adequate job for a long while but soon I wanted the comfort of an overdrive trans.
I started reading about the options out there and discovered the much-neglected THM200-4R. It was used in many a luxo-barge, but also has a pedigree as it was used in the Turbo Buick! In fact the transmission-talk forum on http://www.turbobuick.com was a great source of information for me.
The 200-4R has several advantages:
- Near direct bolt in for a THM-350. No need to trim the driveshaft;
- An overdrive trans. (Of course);
- A deeper first gear than the THM-350;
- A good RPM drop from 1 – 2 (contrary to the 700-4R that has a deeper 1st gear but large RPM drop.)
- Can be built to sustain quite a bit of HP and TQ;
- Has a lockup converter.
Still, to handle over 700HHP/TQ I have roughly $2500 worth of parts in there. Over the years, I also had the trans in and out of the car 8 times… as I learned!
You do NOT need to drop as much as $2500 to bring your THM200-4R up to snuff providing yer not making significant power – say anything under 450HP/TQ.
Do the job right and you will only need to put your trans in there once and worst case scenario twice.
You CAN do this. I had NO prior trans experience and did this all in my basement and on my back in a driveway - alone.
Here’s my advice on doing this:
- Be meticulous, bag, tag and label everything as you disassemble
- Take breaks, especially when things get stubborn.
- Always check everything twice. If a snag develops, you can rule out everything you have 100% confidence in.
- Do ALL the compressed air tests. You can check all your hydraulic circuits before you ever mount the trans in the car. Same idea: if you hit a snag, it might be the Valve Body and that doesn’t require dropping the trans.
- Get the ATSG (automatic transmission service guide) and get the Video. You need both.
- Get a trashed 200-4R for parts. Interchanging the steels of the clutch packs will get your clearances spot on. And you need that!
- Get yourself a pressure gauge for testing 0 - 300 PSI
Other than assorted snapring pliers and inch/lbs + foot/lbs torque wrenches, I did not need any exotic J-tools. If you don’t have compressed air, get the tests done at a buddy’s place. They are easy to do. NOTE: having J-tools would make it much easier!
SLIDESHOW:
http://s223.photobucket.com/albums/dd204/irabel457/Trans Work/?albumview=slideshow
The job was intimidating at first. I had NO prior experience with trans work and I did the rebuild in my basement - I dont have a garage. Now, I have come to the point where working on my trans feels familiar. (I still hate Dexron three in my hair. Yes, I do all this alone, on my back on a European cobblestone drive way. Free tip: collect disposable shower caps from hotels.)
Right, what have in this trans:
- D5 locking torque converter from a Turbo Buick (your converter needs to fit your app – stock might be fine.)
- Hardened stator support. It’s the splined shaft sticking out of the pump. Originals were soft steel and often got munched. A MUST for every rebuild.
- The pump can be stock but needs chrome moly rings to guide the vanes as the stock steel can break.
- An aftermarket pressure regulator installed in the pump. Pressure rises faster and higher.
- An extra wide band: extra clamping force on the drum, a huuuuge servo and adjustable pin + hardened anchor to clamp that band.
- I modified my stock input shaft
- Rollerized center supports
- OD planetary carrier (I broke this one racing… a prosche!)
- OD planetary (This broke with it)
- Forward drum (known to break on hi power apps)
- Bottom feeder sump and deep pan. Prevents sucking air and pressure loss on hard acceleration
- Shift kit. A must if yer making any power.
- A 3 clutch 4th gear. I trimmed my own piston on a lathe and added a clutch. All blueprinted!
All my parts come from http://www.ptsxtreme.com/ Bruce, is the most knowledgeable person on the PLANET when it comes to 200-4Rs. He won't let you down. Period.
Our Lady of Blessed Speed Don't Fail Me Now!
D
PS - you'll need to get the best oil cooler you can as well!