View Full Version : ┐replaced oil seal for differential pinion?

02-23-2007, 12:14 AM
so we replaced the oil seal for differential pinion according to the green bible (at the same time we replaced the bearing retainer gasket) now the drive flange feels really tight we i try to rotate it by hand should it get looser after its driven (we have not adder oil or put the axles in) or should it not have been torqued to the green bibles specs? please advise.



02-24-2007, 11:28 PM
measure preload as per manual.

02-25-2007, 11:53 PM
measure preload as per manual.
leadsprung I'm not sure what you mean. could you explain?

02-26-2007, 07:37 AM
The new gasket is probably not the same thickness as the old one (or the bolts are over-torqued; assuming you used a gasket- replacing a paper gasket with silicone is not a good idea at all) and now you have moved the position of the pinion relative to the ring gear. Another idea is that the new pinion seal is now making contact with the pinion (you DID polish the entire OD of the pinion to a mirror before reinstalling it right?) or is it running on rust, causing a LOT of drag (and super-fast wear of the seal so you are doing this again in two weeks).

You need to check ALL the specs on the diff before installing it in the truck, and be sure you seal is in correctly, is properly lubed, and the pinion OD is polished to a mirror finish.

You have to check pinion height, preload (as stated) and gear mesh with some marking dye or sticky grease (I use the latter) to be sure the contact of the meshing gears is in the center. THIS IS CRITICAL or you will break the ring gear.

The diff is a tricky piece of mechanical engineering, and totally taken for granted. Since you have the proper book, start at the beginning, and check all tolerances as stated in the book.

For future reference, if you need to change the pinion seal, ONLY change the pinion seal, unless you are prepared to do a complete rebuild. I have done this myself several times over the years (in the truck) with no problems.

For all those tuning in, you should always pack the lips of the seal with a good quality grease before installation. This will add to the life, and improve the sealing. Some seals even come with a small tube of silicone grease or this reason....

Also, blue silicone sealer is nasty stuff. As you see in the photo, it has squeezed out of the seal area. Guess what? It did the same thing inside the diff as well. We don't want this stuff in our bearings... I use either Permatex Aviation form-a-gasket or (for really nasty jobs) Permatex Indian Head gasket shellac. The latter is VERY NASTY HIGH-STRENGTH STUFF and should only be used for chronic problems such as aluminum water necks on cast iron manifolds which ALWAYS leak (old MOPARs are well know for this, and this is where I learned the joys of Indian head- nothing else works as well.). Normally, a hammer and chisel are needed to remove the parts when Indian head is used, so keep that in mind... In both cases, use just a light film on both sides of the gasket and the metal parts. Clean the metal parts with acetone to remove ALL the oil; if the sealer fish-eyes on you, clean it again. a very small amount of this stuff does the trick. Let it set overnight (if possible) before filling. It works!!!

03-01-2007, 12:00 PM
Highly recommend Speedy sleeve to put on drive yoke. I did this and no more leaks, even after a new seal.:thumb-up:

03-01-2007, 12:14 PM
Good advice on the speedy-sleeve.

If the yoke OD sealing surface is pitted or grooved after polishing, the speedy-sleeve (or yoke replacement) is the way to go.

Don't forget the aviation form-a-gasket on the yoke before installing the sleeve. No leaks, and no chance of the sleeve coming off this way.

Store the yoke in the freezer overnight, and warm the sleeve a bit with a toaster-oven or (carefully) with a torch. Then it practically drops on!:thumb-up: