W140 Persistant Leak - PeachParts Mercedes-Benz Forum

RyanS · #1 01-29-2008, 10:13 AM

I have a 1994 S600 Coupe that has been professionally serviced several times for the same problem. This problem has been particularly hard to diagnose by my mechanic and I am about to give up on the car completely. He has fixed absolutely every leak he can find. But when the car is parked, without being started or driven for a couple of weeks, the car dumps large amounts of red fluid (enough to coat the garage floor from drivers side to passenger side). It looks like it is coming from the back of the transmission, the power steering pump and associated components have been replaced, and I am starting to suspect tranmsission cooling lines, but wanted to see if anyone has had any actual experience with a similar problem. Incidentally, if the car is driven regularly, it does not leak anything at all. Many Thanks! Ryan

david s poole · #2 01-29-2008, 11:15 AM

that is prob a 722.3 trans and the leak as you describe it comes from the front pump seal after extended cooling down[several days].sorry to say requires trans removal and front pump out.

bobs · #3 05-12-2008, 12:23 PM

Resurrecting a sort of old thread here...

David, I'm facing the same thing on my S420 (722.6). How much labor is involved here? More importantly, is there anything else I should do while the tranny is out?

Peter Guenther · #4 05-12-2008, 12:39 PM

R&R on the trans is about 8.5-9 hrs, I dont know about that trans but i would go for a front clutch pack. Check the lines and mount, shifter bushings

Roger Jones · #5 05-13-2008, 05:56 AM

For what it's worth, MB's Technical data passenger cars manual (0ctober 1993 edition) gives:

722.362 for the S600 Coupé
722.366 for the S420 Sedan

Hatterasguy · #6 05-13-2008, 01:34 PM

The trans in my SDL does this. If the car sits for a long time the front seal which I have replaced BTW will start to leak and leave a nice puddle. If I drive the car its dry as a bone.

Depending on how much its leaking I would just ignore it. If its dumping out 3-4 quarts I'd fix it though. You need to drop the trans to get at them, which on the W140 doesn't look like to huge of a job.

Edit: just saw the person who brought it back to the top has a 722.6, fix it. That trans doesn't have a built in dipstick so keeping an eye on the fluid is a PITA. I read the first post I think the S600 has a 722.3.

bobs · #7 05-13-2008, 02:33 PM

Yes, its a 722.6. My problem is it started leaking several tablespoons a day and the pump is getting very loud. The car is currently at the dealership getting the seal replaced. It's going to be expensive, which is why I asked if I should do anything else while they have the car that far apart. In for a penny, in for a pound.

bobs · #8 05-14-2008, 09:50 AM

I just heard back from the dealer. It looks like the bearing on the input shaft let go which is what tore up the seal and caused the leak. They let me inspect the transmission and the bearing is indeed shot. They're quoting me about $6k for a reman unit, which includes labor.

Is this "in the ballpark" ? At this point I'm stuck between a rock and a hard place because 1) I already owe them for the work they've already done, and 2) the car is not driveable in its current condition.

Hatterasguy · #9 05-14-2008, 12:43 PM

Thats about what I would expect the dealer to charge. Thats what my grandmother paid the dealer to change the trans in her Jag.

If you can tow it out of their you could probably find a shop to swap it for $4k or slightly less. I *think* rebuilds can be bought for $2,500-$3k.

However since your already commited at the dealer its probably impossible or not worth it.