Hi!

I will be trying to replace the transmission fluid and filter for my 85 380SE.
I notice that there are 6 bolts around the transmission pan and I assume that I'll need to unfasten these bolts.
The transmission fluid is leaking around the pan gasket, so I'll need to replace the pan gasket too.
What do I need to pay attention when replacing the gasket so the oil pan won't leak?
Also what is the detailed procedure to drain the transmission fluid from the torque converter?
I appreciate your help.


Lin
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85 380SE

You have two drain plugs one is at buttom of trans oil pan other one is at convertor first drain trans fluid from trans pan next use a screwdriver turn convertor from the window ( front of trans oil pan) until you can see the plug drain convertor oil,remove six bolts & oil pan now you can change filter three screws,clean oil pan reinstall pan with new pan gasket never over tight the six bolts it will damage the oil pan,refill trans fluid from under the hood put 4q first then start your engine add other 2q and check again add more if need. hope this help

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MB STARS Master Guild Technician,17 years MB tech
14 years independent shop owner

Just to add to the importance of proper torque settings on the pan bolts. I over tightened the pan bolts while I was under the car for some other reason. I split the gasket and didn't notice until I had driven several miles the trans started slipping REAL bad due to the fact I had lost about 5 quarts of fluid. Luckily replacing the gasket and a fresh fill of fluid worked. No damage because I caught it soon enough, although I probably shortened the life of the transmission a little. Just thought I would stress this point.

A few points I'd like to make:
There are 2 sealing rings which must be replaced when doing this, one aluminum and one copper. The aluminum one is for the torque converter plug, the copper one is for the trans pan plug. On the torque converter, make SURE the old aluminum one is removed, it may stick to the torque converter and be difficult to remove. Sometimes it sticks to the plug, but the most problem I have is when it sticks to the torque converter, which happens more often. The torque spec on both plugs is 14nm. The torque spec on the trans pan bolts is 8 nm, I usually bump it up to 10nm. On an older Benz like this, you may find it beneficial to chase the threads on the transmission case for the trans pan bolts. I believe these are M8X1.25 bolts. The aluminum can start getting corroded on these bolt holes and cause it to be difficult to get the pan to properly squeeze the gasket into place. Sometimes it can make it hard to get the bolts threaded back into the case at all!
When putting in the fresh ATF, put in 2 or 3 quarts, then start the engine, then continue putting in the rest of the fluid with the engine running. Otherwise you will overfill the case and it will run out the breather, because the torque converter holds so much of the fluid and the pump won't pump it in there without the engine running.
To align the torque converter with the access hole in the bell housing, MB Stars method will work, I usually turn the engine over by hand using a socket and breaker bar on the crankshaft front bolt, but it may be difficult for you to find the tools required to do it either way, specially on a Diesel.
Another simpler though more frustrating way is to have an assistant "bump" the starter while you watch the access hole and torque converter drain plug to coincide with each other.
Gilly

Hi! MB STARS, 190guy and gillybenztech,

Thanks for your very helpful information. Because of this precious information, I successfully replaced the transmission fluid and filter today.
It took me 2 hours to complete the task and surprisingly there is no leak.
One very important thing I want to share with everybody is that if you notice any transmission problem, you should change fluid and filter first before you start any repairs. The whole kit only costs $22.00.
I got 2 transmission problems before I change the fluid. After the change, both problems went away.
One problem was the hard shifting, the other problem was that I couldn't move the gearshifter from "D" to "P" sometime.
I even got the advice from some transmission experts to rebuild the transmission. That's $2000 at least.
The transmission runs very smoothly now.
Thanks! Have a happy labor day!

Lin

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1985 380SE

Glad to hear that it worked for you. Anytime a small investment of time and cash solves a problem, I think thats a good thing. Congrats on the fix. I have found that with a little time, patience, help from this forum, and a few parts from the Parts Shop and Fastlane almost anything can be fixed on my 201.

Have a good day!

That was good information. This morning I looked under to get the torque convertor plug. I saw the plastic cover and removed it but I have difficult time turning the enginee to see the drain plug. Turning the enginee by the crank shaft is not possible as I must remove the radiator(too hard). Running the starter was not sucessful also because I have no help. How do I turn the convertor by screw driver? It seems that there is nothing that I can anchor the screw driver to.

thanks