Rear Main

[6.5 Detroit Diesel]

We have an '83 6.2. Bodywork and paint is done, rear axle swap to an Auburn. Only thing left is the rear main seal which is leaking quite badly. I have the tranny, clutch, flywheel, all of out the way. But I am a little stumped as to how to actually remove the seal. Is there some sort of special trick for this?

[DmaxMaverick]

Which seal do you have in there now? Rope seal, or rubber/steel?

Remove the rear main cap for either.

The rope seal can be pulled out, just make sure you get all of it and it doesn't break. Compare the rope circumference with your replacement seal, and there should be no pieces missing from it. If there's any doubt, you'll have to drop the crank to clear the groove.

The rubber/steel seal should not be difficult. You should be able to start it's removal by pushing on one end (tap with a small hammer/punch), which starts to push it out the other side. Rotate it out, don't try to pull it straight or it can bind. If it doesn't move with reasonable force (not enough to deform anything), you'll have to loosen all the main caps to relieve pressure on the seal. Some folks use the new seal to push out the old, but I don't like this, as the feel is not as good (if there's resistance, you can't tell if its the old coming out, or the new going in). DO NOT rotate the crank while it is loose, you could dislodge the main bearings, and destroy them on tightening. Also, avoid any impact on the crank (like with a hammer), as it can also dislodge the bearings. You should not have to loosen the crank any more than necessary to allow it to drop less than 1/16" at the rear. Most often, the tension on the belts will be enough to lever the crank down at the rear (if the belts are on it) Use lots of lube when inserting the new seal. Place it on the bottom of the crank and align it with the groove. It should rotate into place with minimal force by hand.

[6.5 Detroit Diesel]

So....
We have to drop the oil pan? I was hoping there was a way to do it otherwise. ;)

[DmaxMaverick]

Only if it's a 6.5L with a one piece RMS. Removal of the flywheel is all. All 6.2's had the rope seal, or a 2 piece seal. Either requires removal of the rear main cap, which incidentally, requires pan removal.

[john8662]

Yeah... I'd prefer removal of the pan above transmission/xfer case n stuff...

But, that's where it's at.

Once you get good at it, you can come fix the one on my '91 6.2 suburban that's just starting to develop the leak, or hand the beer while I do it, take your pick...

John

[6.5 Detroit Diesel]

It's a two wheel, so that made it easier.
Given the choice, do I have to hand the beer, or could I drink it and watch you work? :D