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TR4/4A Transmission and Overdrive Capacity


Luke Skywalker
Country flag
I drained my transmission through the underside O/D plug, and now it will only take 1.5 quarts before fluid spills out of the filler hole. I can only conclude that I should've pulled the standard underside plug as well. The unit, transmission and overdrive, must retain lubricant when only one of the two plugs is removed. According to the manual, the correct capacity is slightly over 2 quarts, so I must have retained about .5 quarts. Does this sound correct? Thanks all.


Great Pumpkin - R.I.P
Yup. I don't know exactly how much it holds, but there is definitely oil trapped in the gearbox. The passage between the two units is well above the bottom.

If it's any consolation, the Ferguson tractor I'm working on has 3 drain plugs and they all have to be pulled. Then even after sitting overnight with all 3 plugs out, it dumped oil all over me when I removed the hydraulic pump. Two showers later, I've still got oil in my hair! And there is still quite a bit of oil, sludge and dirt visible inside.


Luke Skywalker
Country flag
I've never done it but I read somewhere about lifting the back and then the front of the car to level out the oil. Tom

Alfred E. Neuman

Jedi Trainee
I was actually about to pull my TR4 into the shop on Saturday and change all the fluids. I've got a few liters of GL4 for the diff and trans/OD. I'm going to pull the trans drain and the OD plug so I can look at the filter screen.
Is there any special procedure for refilling if you've drained both, or is the trans fill plug high enough that by the time oil is up to that level it's definitely flowed back into the OD?



Great Pumpkin - R.I.P
Takes some time for the level to equalize, definitely longer than filling the main box. I generally just overfill a bit and call that good enough, but its best to let it sit level and check again after a few hours.

Graham H

Jedi Warrior
Country flag
Or fire it up and let it run for a minute or two,that should get the oil every where it needs to go.


Alfred E. Neuman

Jedi Trainee
Or fire it up and let it run for a minute or two,that should get the oil every where it needs to go.

That's a good idea. That's actually the way we have to fill all the Mercedes 722.9 transmissions. Fill it up cold, hook the computer up to it and run it to a temp of 40 degrees C. When just a dribble comes out at 40 C, you're done.
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