Rear main seal job

[Nikki]

Has anyone changed the crankshafts rear main seal before? Mine is leaking but im not sure if i need any fancy tools, or do i just pick it out with a screwdriver?
Thanks

 

[Mutant Pony]

You thread a couple sharp screws through the seal and it pulls it right out. Just make sure the threads don't contact the crank/seal surface!
The problem is that these seals don't just leak. If the rear main seal is leaking it is probably a simptom of something else. Has the pcv valve been replaced? is the oil broken down? Is it actually a rusted through oil pan? These are all more likely problems.

 

[Nikki]

well when i took off my flywheel i kind of noticed every seal is leaking lol. My valve covers are badly leaking, the rear main, the oil pan... I'm going to change my PCV valve too, just incase its causing problems..
Now you got me nervous that there could be something wrong internally...
hmm....

 

[Andres629]

Not likely any of these... the rear main on my 2.9 started leaking... I took the tranny off and noticed the same... EVERYTHING was leaking. Replaced all the lower seals and voila, no more leaking. I don't think they'd ever been done in the life of the truck.
While you're at it, change the front main as well.

 

[Mutant Pony]

Well, if your 3.0 sits around alot (like a still running 2.9 must have done) it is a good possibility that your main seal is bad.
I have run my old '86 3.0 at 6000 rpms for extended periods of time, It sits alot, it has well over 200,000 miles on it and doesn't leak much out the rear main. If anything, it may have been seeping a little for a long period of time.
If you already have it apart, change the seal.
If everything is leaking it is most likely a case of running with broken down oil.