How do I get my Transmission pan gasket to stop leaking? - PeachParts Mercedes-Benz Forum

karl2274 · #1 10-28-2007, 08:04 PM

Ever since I purchased my 1985 300td it has leaked transmission fluid from the gasket. This weekend I replaced the gasket and the filter thinking that a new gasket would stop the leak. When I started the car after refilling the transmission, it started leaking from the same place on the gasket as before. It seems to be coming from right above the middle pan bolt on the drivers side of the car.

What am I missing?

Matt L · #2 10-28-2007, 08:08 PM

Ensure that the pan flange is flat. If the bolts are overtorqued, it will distort the pan. If it is distorted, it can be straightened.

Then ensure that you put the bolts in with the correct torque. My 722.4 specifies 8nm. Yours may be different, but note that 8nm is not very much torque. Start them all at a much lower torque to seat the gasket, then torque them down to spec.

vstech · #3 10-28-2007, 08:45 PM

yup, flat pan is best. pull it and verify it's flat all around. also look for a cracked case there. if all else fails, clean it well with denatured alcahol or acetone, and put some ultra blue gasket sealant on there REALLY thin.

karl2274 · #4 10-28-2007, 08:54 PM

I suspect the pan is distorted. should it sit flat on a countertop or piece of glass? What is the best way to check for distortion?

spugeddy · #5 10-28-2007, 10:34 PM

The only other thing it may be is too much fluid level

Is it possible the system is overfilled?

Matt L · #6 10-28-2007, 10:38 PM

Use a straight-edge on the pan to check it at all angles. Setting glass on top would also work, but not any better. You won't be able to see the problem very well with the pan inverted on a flat surface.

karl2274 · #7 10-29-2007, 08:16 AM

The fluid is slightly over the top line on the dipstick. If it is over filled, will the leak stop after removing fluid? or has damage been done?

spugeddy · #8 10-29-2007, 02:02 PM

Not real sure, I have read that recently though about too much fluid could cause leak at trans pan.

Can anyone validate that?

vstech · #9 10-29-2007, 02:07 PM

Quote:

Originally Posted by karl2274

I suspect the pan is distorted. should it sit flat on a countertop or piece of glass? What is the best way to check for distortion?

it's best to just look at the pan, the bolt holes should not be bowed in towards the transmission. they should be flat. if you have a vise or anvil, just put the pan lip on there and whack them flat with a mallet/hammer.

xtreme barton · #10 10-29-2007, 02:22 PM

ill be doing this job on wed. and i think i have the same problem .. i had a small leak an i tried tightning the bolts a bit more to stop the leak .. no bueno as it made it worse .. thanks for the thread cause i would have probably just slapped it back into place .. ill def check the straightness and pound out any inward bolt holes and use a little sealer to help me out a bit more .. cant wait till this thing is leak free

pawoSD · #11 10-29-2007, 03:10 PM

In our case we replaced the pan, and made sure all the bolts had the right washer on them...and it finally stopped leaking.