Rear main seal leaking, Trans Slipping
Thread Starter
Newbie
Joined: Sep 2005
Posts: 3
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Rear main seal leaking, Trans Slipping
Hey all, my 02 started leaking oil and the mechanic tells me its the rear main seal, shortly thereafter, the trans started to slip when starting out under stress, like uphill (even a small grade) Any chance the 2 are related, or is 237k the most I'm gonna get from it? I had the trans fluid checked and it's full, and was replaced along with the filter at 180k.
Member
Joined: Jun 2013
Posts: 81
Likes: 5
1998 C280
A leaking RMS leaks engine oil into the bell housing and should not affect transmission operation. I think the two issues are separate. Consider carefully whether the value of the car versus the cost of a trans rebuild. The RMS is an easy fix when the trans is out for repair.
MBWorld Fanatic!
Joined: Dec 2003
Posts: 3,275
Likes: 236
From: BC, Canada
2003 C230K Coupe Orion Blue
Check the transmission level and top up if needed. You'll need a special (works across different MB models) dipstick.
Transmission fluid dipstick
If the transmission is dropping out of gear, it's probably the pilot bushing leaking. This lets transmission fluid wick up the cabling into the control module where it causes weird shifting problems. I thought my transmission was on the way out but this fixed it. The module itself is located under the passenger seat footwell for a LHD car. There are 3 versions of the pilot bushing. Pick up the latest from the dealer for a few bucks.
Transmission shifting problems
Transmission Control Unit (TCU) removal
There are some other threads out there. This is a common problem.
Your car is high mileage. You're way overdue for a full fluid change anyways. I would recommend getting it done if you plan on keeping the car.
Rear main seal leaks are rare, but they do occasionally happen. Either keep topping up, or have it replaced. Unfortunately you'll have to pay a specialist as it requires dropping the transmission out of the car, and requires a special tool to press the seal in properly and evenly. If you're doing it, might as well change out the transmission flex discs (2 in total) as well as the rubber rear engine mount.
Transmission fluid dipstick
If the transmission is dropping out of gear, it's probably the pilot bushing leaking. This lets transmission fluid wick up the cabling into the control module where it causes weird shifting problems. I thought my transmission was on the way out but this fixed it. The module itself is located under the passenger seat footwell for a LHD car. There are 3 versions of the pilot bushing. Pick up the latest from the dealer for a few bucks.
Transmission shifting problems
Transmission Control Unit (TCU) removal
There are some other threads out there. This is a common problem.
Your car is high mileage. You're way overdue for a full fluid change anyways. I would recommend getting it done if you plan on keeping the car.
Rear main seal leaks are rare, but they do occasionally happen. Either keep topping up, or have it replaced. Unfortunately you'll have to pay a specialist as it requires dropping the transmission out of the car, and requires a special tool to press the seal in properly and evenly. If you're doing it, might as well change out the transmission flex discs (2 in total) as well as the rubber rear engine mount.
Last edited by slammer111; Apr 9, 2020 at 03:33 AM.
