Rear main seal

sahls01gmc · November 14, 2013

How difficult on a scale of 1-10 is it to replace the rear main seal on my truck? To me, it seems pretty straight forward. Unbolt transmission, replace seal, bolt transmission. Obviously, other steps apply, but is there really more to it than that?

Does anyone have any tips to offer when tackling this?

Any help is greatly appreciated!

sahls01gmc · January 24, 2014

A guy at work mentioned the excessive oil could be caused by a PCV problem. Any merit to that claim? I suppose I should change that anyways since it is a $2 part.... But would a bad PCV valve cause this? Obviously a seal was the weakest point, but was there an increase in crankcase pressure to cause it to fail?

sahls01gmc · January 22, 2014

You might as well do other items in the vicinity while you're there.

Mine was done in 2011 when the trans was replaced, so you might want to wait until that is needed.

I wish I had replaced the trans mounts then and a few other items.

What items in the vicinity do you suggest? I was hoping to wait until Spring, but it is now puking oil so I can no longer hold off. Probably going to tackle it this weekend. I will look at my malfuntcioning Transfer Case Shifter Motor while I have it all down.

How often should I replace the u-joints on the driveshaft? I changed them at 125,000 when they started squeaking. I'm at 255,000 now. They are not squeaking, but perhaps waiting for them to squeak is not a wise decision.

Thanks to everyone for the tips and suggestions!

gmtech4 · November 15, 2013

have you ever done anything like this before ?,im guessing not by your questions

its not a first time job to do ,,,,,especially on a garage floor ,,,

you should rethink it

TurDuckEn · November 27, 2013

It's not really that bad. If you have a good jack, transmission jack, etc. you'll be fine.

The seal is cheap too http://www.gmpartsonline.net/parts/2001/Chevrolet/Silverado%202500/Base?siteid=215055&section=ENGINE&group=CRANKSHAFT%20%26%20BEARINGS&subgroup=CRANKSHAFT%20%26%20BEARINGS&component=REAR%20MAIN%20SEAL

But if you took it somewhere, I'm guessing they'd charge about a grand in labor.

jhm · November 15, 2013

I did it on my "65 Mustang, easy. This truck? wouldnt try.

gmtech4 · November 16, 2013

good luck to ya ,work safe

white1500 · December 2, 2013

You might as well do other items in the vicinity while you're there.

Mine was done in 2011 when the trans was replaced, so you might want to wait until that is needed.

I wish I had replaced the trans mounts then and a few other items.

sahls01gmc · November 15, 2013

I've pulled the engine on my old FWD car back in High School many times. I've had to do it to replace the engine, the clutch, the transmission...and even the water pump. I'm very comfortable with tools. I'm just curious what pointers anyone has from ones that have done it on these trucks. Sorry I didn't give you the comfy cozy feeling up front. No, I'm not ASE certified or anything, but I do know my way around under the hood if you know what I mean.

I do appreciate the feedback, it gives me some idea of what to expect.

Thank you!

Dnt · January 25, 2014

Recently had this rear seal replacement done on a 2009 5.3 (under 100k so warranty item) it took the dealership 2 days and they had parts scattered all over the shop. They were also replacing the oxy sensor but it was seized in the pipe and they bent the line trying to get it out so they also replaced the y joint pipe with the catalytic converter. I thought when I heard about the extra parts that it could just as easily have happened to me if I were doing the job myself. Then of course after studying on that for a while I immediately traded that succa in on a 2014 like a good little consumer is supposed to. So Sahls01gmc have you driven one of the 2014's yet? Come on man GM needs the sales LOL Seriously though you should check the oil sending unit before you pull the tranny I believe it is towards the back of the engine and if it leaks can easily be misdiagnosed as a rear main leak so I have had heard..................

TurDuckEn · December 23, 2013

You might as well do other items in the vicinity while you're there.

Mine was done in 2011 when the trans was replaced, so you might want to wait until that is needed.

I wish I had replaced the trans mounts then and a few other items.

This is a smart suggestion

sahls01gmc · January 28, 2014

Thanks Dnt! I have not driven a new one yet, but they do look pretty sexy. I'm spending WAY LESS a month keeping this one running vs a truck payment, so I'm gonna keep it this way for a while. I've thought about the oil sending unit, are you saying the oil pump? Just making sure we're talking the same language. That would be an easier repair.

This did happen the other day. When taking off from a light (not launching, just normal take off) the transmission ( or so I think) almost seemed to mimic a blow off valve sound when it shifted into 2nd. The first time it happenned I thought it was the car next to me or something else because I wasn't expecting to hear that. It did happen one other time a day or two later. No other weird shifts or any other vibrations, just those 2 instances. Any thoughts what this could be?

Huge thanks to everyone's input and help along the way.