I'm trying to figure out where the leak in my trans is. It is from the passenger side rear and only seems to leak while driving(no spots on the ground when parked). Is there any gaskets or seals that can be replaced back there? It is extremely hard to see as the rear crossmember is right below there. If I had some sort of parts schematic it would sure be helpful. I thought I had a full set of factory manuals, but there is nothing at all on the transmissions. Maybe I am missing one? Anyway, if anyone could point me in the right direction I would be grateful. Thanks-Scott

Clean it and trace the leak.

A typical leak on the passenger side is the o-ring at the base of the bowden cable. You talk about the crossmember so maybe your leak is further aft.

Sixto
87 300D

There's a test port for operating pressure above the middle pan bolt, the secondary pump is right above the crossmember, kickdown solenoid is below the secondary pump right above the pan mating surface, B2 piston is ahead of the secondary pump...

Sixto
87 300D

The leak is definitely at the right rear just above the crossmember. There appears to be some sort of cover there,but I just can't get a good view of it. It only leaks while driving, and especially on hard acceleration ( can smell the fluid burning on the exhaust pipe). So- does anyone know where I can get a good schematic of the trans so I can troubleshoot this problem? I'm sure I can figure it out if I have a good picture. I had a spare trans, but unfortunately I gave it away!!!

Sixto- I was posting my reply to your first post while your second post came in! Do these parts have seals, and are they replaceable on the vehicle or do I have to drop the trans? Any advice is greatly appreciated as it is using about a quart every 500 miles now! Thanks-Scott

sounds like it could be the O ring for the B1 servo. I have seen them leak. There is another cover for the governor as well behind that. As the others have said clean the area off and see if you can see where it is comming from. If it's only leaking going down the road it does sound like its when under pressure. Also, check the cooler line on that side. .while it is more forward, maybe it is blowing back?

OK-I'm gonna clean everything and see if I can tell what is leaking. Now back to my original question-DOES ANYONE KNOW WHERE I CAN GET A SCHEMATIC FOR MY TRANSMISSION? Thanks-Scott

CHECK YOUR PM

Sixto
87 300D

As you noticed the factory service manual does not include much info on the transmission. If you live in the US then subscribe to the Mercedes Electronic Parts Catalog online for free at http://epc.startekinfo.com. There is a pretty good parts breakdown and exploded diagram of the transmission. The next step would be to get the ATSG transmission manual from one of the online transmission parts suppliers like bulkpart.com.

Like everyone has said if you clean it real well then drive around for a while you should see where the leak is coming from. Unfortunately there are a number of things that can and do leak on that side of the transmission and they will run down and back to about the same place. You will probably have to remove the crossmember and lower the back end of the transmission to really see what is going on. A strong light and a mirror will come in handy. There is a pictorial on the dieselgiant site that shows replacing the B2 piston. This is a common leak and the the pictorial will give you an idea of what is involved with servicing that side of the transmission.

fdanielson- Thanks for the link. I'll give that a try. Sixto is going to email me a diagram as well. I think I will be able to figure it out now. I had no idea where anything was on the trans due to my lack of a manual. I was worried that maybe the case was cracked or something like that, but now that I know about all those seals it's just a matter of figuring out which one. I think I'll replace all of them while I am at it to be safe. The old $50 wagon is about 500 miles shy of 300K now so I certainly can't complain!! These Mercedes sure are great cars! Thanks to this site and all who help out-Scott