so I just spent a week dropping the transmission on my 2001 suburban 2500 with the 6.0. so i could replace a leaking rear main seal. while I was down there I also replaced the oil pan gasket and oil cooler gasket and all the universal joints. put the rear plate gasket in and the new rear seal. put it all back together and its Leaking worse then before and now I seem to have a transmission leak as well. What gives???? Any thoughts on what I might have done wrong before I attempt again.

 

It gets really frustrating when these things happen. You have done a lot of work on your truck.

When you installed the new main seal, are you sure that you got it in square in the housing. I also assume that you placed the seal with the right side in. If you install it backwards it will wick oil out.

Did you clean the outter surface of the crank before installing the seal. It is a good idea to clean it with 000 steel wool and remove all of the old dirt. Then wipe it off with a clean cloth and brake cleaner.

When installing the new seal, use a marine grade grease around the inside lip, to aid in break in of the seal and to help prolong its' life.

Good luck with the repair.

 

hard to say without taking it apart and looking, i do know its very important to get the seal centered in the backing plate

For peace of mind before you tackle it again I would put some dye in the oil and run it a bit that way you can hit it with a UV light and see where the leak is exactly since those are pretty hard to properly diagnose sometimes.

 

Where did you buy the seal from. At work we would only use a dealer seal for something that required that much work. Aftermarket seals are hit or miss sometimes they work sometimes they do not. If I remember correctly the rear main seal was updated and came with clear instructions on which way to install it as it is different then the original.

 

the 8.1 i did a few weeks ago was an updated OE seal i'd assume they're similar

 

Yes this was an updated seal. Very Cheep looking all plastic but I did follow the directions that came with it and made sure the correct side was out.

 

When I did this the first time I did not remove the transmission all the way. I just slid it back as far as I could to get access to the rear plate and seal. I think this time I will remove it all the way. Is there anyway to remove the transmission without disconnecting the transfer case (its a 4x4) or if not are there any seals or gaskets that will need to be replaced?

 

in the long run its easier to remove the tcase and yes there is a mounting gasket between the transmission and tcase

 

can I start and run the engine before I put it all back together to see if the seal is leaking?

 

yea you'll just have to hook the starter and exhaust back up, i actually did the same thing. it already had dye in it so i let it idle for about 5min then held the throttle at 1500rpm for about 20 and hit it with a uv to double check no leaks