Help in installing a bone dry rebuild transmission


Well-Known Member
Installing a rebuilt 4L80 transmission:

Do I pour a QT of ATF into the bone dry Torque convertor??

How much does a bone dry 4L80 get??

Should I run synthetic ATF??

And I am under the impression I put a few QTs of ATF into the transmission, and then before starting it check to see if my dip stick is reading full…??

And as my oil lines and coolers are not dry should I flush them before running the new transmission?

Note the old transmission was running fine so there is no junk in the fluid. I am just upgrading from a 130K good 4L60e to a fresh fully upgraded rebuild 4L80e with a rebuilt torque convertor.

Thanks for any and all help.


And Yes this project HAS taken 3+ years..and dreamed of and planed for about 29 years. The engine build was started in 2004.

Frankly after the first year 3 years ago I began having poor health, and this engine and transmission with a swap from a 4L60e to a 4L80e with an add-on US Gear Dual Range overdrive is a nightmare job, new transmission mount new drive shaft, etc. All the hook ups a swap of PCM etc. A major Herculean task!!

And an engine swap from a TBI to a TPI system with ALL the problems of converting the Vans PCM, hookups, is also A Major Herculean task.

Then there is my plan on rebuilding the interior, for the third time, changing the bed, from a single to a queen, rigging a stand for my sleep machine, and a batter system to get a full 8 hours if not AC is available, putting in a window heat pump, rigging a start stop thermostat controlled engine system so that we can have either heat or cooling from the vans own systems when we cannot get a hook up of 120V AC for the Heat pump.

Then there is still a worry about all the hoses and so on after sitting for over 5 years….

And my plan of switching from an engine drive fan to an electric fan system from my 2000 Mercury.

And I think I need a special Hydro power steering and brakes pump.

Quite frankly I fear I have taken on more than I can handle.

  • Automatic transmissions:
    • 4L60-E: 11.2 quarts.
    • 4L70-E: 11.2 quarts.
    • 4L80-E: 13.5 quarts. 6.3 to 7.7 quarts for just the transmission.
    • 4L85-E: 13.5 quarts.
    • 6L80: 12.2 to 12.4 quarts.
    • 8L90: 10.9 to 11.4 quarts.
    • 10L80: 11.5 to 12 quarts.
  • if you don.t have one get a transmission fluid funnel


fill the trans with about 7 quarts , you don't need to fill the torque converter , but it's generally going to speed things up, if you put 2 quarts in it as its installed, once the engine starts, it pumps fluid through the trans and converter, having a couple quarts in the converter on start-up helps marginally,as it helps prime the transmission fluid pump, just keep adding the trans fluid to the trans as its filling the converter very rapidly,once the engine starts, so you'll want to fill the transmission as the trans pumps fluid into and through the converter until the trans reads full at idle. remember to hook up the trans cooler lines and verify no leaks

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Thanks. I believe I was able to get a 4L80 dip stick and dip stick...but not 100% sure, I have a about 4 sticks and two tubes from other junk yard Vans. (they are longer to be reached from the front of the engine).

I saw somewhere a bit of filling the transmission to the top of the fill hole, and then putting in the tube and stick and that will check rather you have the correct dip stick.

I thought it was here.



  1. Park vehicle on level surface, engage parking brake and start engine. Leave car in neutral or park. Let engine warm up and continue to run throughout operation unless vehicle's owner's manual says otherwise. (Be aware that some automatic transmission fluid levels are checked with the engine off. Check owner's manual.)
  2. Locate automatic transmission fluid dipstick, typically near where the transmission or transaxle meets rear of the engine. It looks similar to the oil dipstick.
  3. Remove automatic transmission fluid dipstick. Wipe clean, reinsert fully and remove again. CAUTION: FLUID MAY BE HOT!
  4. Observe markings at end of dipstick. Your dipstick might have two markings for "full"—one warm, one cold. If the automatic transmission fluid level does not come up to the "warm" line, you'll need to add automatic transmission fluid.
  5. Insert long funnel into automatic transmission fluid dipstick hole. Carefully add automatic transmission fluid in small increments and recheck level each time until fluid level reaches "warm" line.
after a few minutes of run time driving slowly and going through all the gears verify the trans fluid levels are up to between a 1/4"-1/2" above the transmissions oil pan gasket level on the transmission sitting on level ground
the dipstick markings and depth should have been verified with the dipstick and its tube installed with the transmission oil pan off during the rebuild or transmission filter change etc.



4L80E (1991-1996)
Fitting Location Thread Size Flow Direction
Upper ¼" Pipe Return/in
Lower ¼" Pipe Cooler feed/out

4L80E/4L85E (1997 & later)
Fitting Location Thread Size Flow Direction
Rear ¼" Pipe Return/in
Front ¼" Pipe Cooler feed/out

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Should I run synthetic ATF??
That's what I did for my TBucket was use a Valvoline Full Synthetic. You might find the research I did on ATF useful at the link below.

I had both a new engine and new trans for my first startup. So I filled TC with what every it would hold in a vertical position and then filled the pan. I had an aluminum pan with extra capacity, so probably about 4-5 quarts of Valvoline Full Synthetic fluid. But I was also ready to start filling the trans immediately after the engine started. I had one person assigned to this task only, filling it to within about 2 quarts of documented dry capacity before checking the level with the dipstick. I had other things to attend to.


I had modified the dipstick tube so it was very short. That's why the clear plastic tube runs under the car. in the photo above.


And as my oil lines and coolers are not dry should I flush them before running the new transmission?
It would only necessary if you suspect the previous trans had metal circulating. Otherwise you would be fine by just installing them as they are.