I have a 2002 2500 with the 5.9. I noticed a oil spot on the driveway the other day. It was about 3" in dia. It appears to be coming from the rear main seal. The flywheel cover and the front of the transmission pan are wet with oil. The truck only has 39000 mi on it. Any idea why the seal would go bad with such low mileage? I haven't crawled under the truck yet (its in the the teens here) to see if it could be anything else. Any other parts it could be leaking from?

 

It could also be leaking from the oil pressure sender, which is pretty typical occurance. The oil will flow down the backside of the block and make it look like a rear main seal problem.

 

Any idea why the seal would go bad with such low mileage?........Many seal failures are caused by incorrect oil level(overfill) or clutch heat (6spd w/clutch slippage?)
Any other parts it could be leaking from?...... Transmission? Oil sending unit?

Just some ideas.

 

I just had the oil changed and checked the level after. It was not overfilled. It has an auto. so no clutch to deal with. I will have to get under it to check the sending unit. Is it on the back of the block or side? It is freezing outside and want to eliminate how much time I spend under there. I guess I am just praying its not thje rear main. I know they are expensive, any idea on a ballpark figure?

 

Sending unit is on the back of the block on top, where the bellhousing meets the block.
The rear main seal itself is cheap. Labor is the expensive part.
On an auto it would be a little easier though, just drop the tranny and flex plate and replace it that way.
No idea on shop labor, I'd guess they'll wanna charge around 6 or 7 hours labor as a rough guess.

 

I dont know how mechanically inclined you are...but if you have a garage and a good supply of tools it isnt that bad of a job....here's a step by step i found AFTER i did mine ...Took me about 8 hours with cleanup....

http://www.pavementsucks.com/tech/rearmain.php
Good Luck!!
--Dylan

 

THE REAR MAIN SEAL ISN'T A BAD JOB AT ALL. THE HARDEST PART IS WRESTLING WITH A TRANSMISSION WITH ONE PERSON. IF IT IS THE REAR MAIN SEAL, IT IS A TWO PIECE ROPE SEAL ON THE 5.9s. AFTER YOU GET THE UPPER PIECE OF THE SEAL IN, YOU ARE SUPPOSED TO USE A DAB OF SEALANT WHERE THE UPPER AND LOWER HALF MEET. DO NOT USE SILICONE. USE LOCKTITE STUD AND BEARING MOUNT. SILICONE OF ANY TYPE WILL WREAK HAVOCK WITH THE RUBBER CASING AROUND THE WIRE ROPE ON THE SEAL. ANY RUBBER FOR THAT MATTER.SEALS WILL GO BAD @ LOW MILES FOR 3 REASONS: 1: BENT CRANK ( VERY HIGHLY UNLIKLY ) 2:MOTOR SAT AND RUBBER DRIED OUT. 3:THE RUBBER / WIRE SEAL UN-VULCANISED. THESE SEALS ARE VULCANISED THE SAME WAY MOTOR MOUNT ARE.

 

Thanks Dylan, that does not look bad at all. I thought the tranny always had to come out. Nothing sucks more than pulling a tranny with no lift, on your back in the cold. I will have to keep any eye on it to see if I can make it to spring. I have a garage but it is 1 stall and has my MG I am restoring in it.

 

Has anyone had to pay for labor on replacing the rear main seal? I wondering what the labor hours a dealership or mechanic would charge for? I know the DIY articles say 4-6 hours, but a professional in a professional shop should be less, right?
Thanks

 

Thanks to you all mine turned out to be just a oil sending unit, not a rear main like I thought..