Replacing the pinion seal, again, but found out why

[Rich69shortfleet]

I've probably replaced the pinion seal three times in the past 10 years. New one starts out okay and then begins to drip. Eventually it oils down the whole center of the axle. Never lose enough to have to top off the fluid, but messy and annoying.

So, today it was time to replace it again and change the fluid while I was at it. Drained the fluid and sealed up the rear cover before tackling the pinion seal. Got things apart without much trouble. But while I was mucking about, I knocked the vent and vent hose loose. I took the vent fitting and hose to the bench to clean them up before reinstalling and found that the vent was entirely clogged. No wonder the pinion seals keep leaking! Probably took me longer to remove and reconnect the little bolt and bracket that holds the upper part of the vent hose than it did to reinstall the pinion seal. Bolt is in a crappy location and probably hasn't been removed since the truck was built.

Hoping for better seal performance moving forward.

[PbFut]

Easy to overlook. Good tip!

[MySons68C20]

Originally Posted by PbFut

Easy to overlook. Good tip!

Thumbs up!

[Rich69shortfleet]

Filled it with fluid this morning and drove it to run some errands. Logged about 50-60 miles. Dry as a bone and no funny noises. The front of the center unit was about 189 degrees after a long drive, don't know if that's normal. Never measured it before. After a long drive home it was only 170 degrees.

Also, how much vertical movement should there be in the center carrier bearing? It isn't making any noise and the rubber seems in good shape, but I can move the driveshaft about 3/8-1/2 an inch up and down.