2001 silverado 4wd. 105k miles. Left front axle leaks, I've replaced the seal 3 times with seals from Napa and GM. The axle shows no sign of wear. Any suggestions. I am an experianced mechanic with proper tools.

 

Are you sure it's the axle seal leaking?
I had an 02 Silverado 1500 4wd and it ended up being the plastic vent plug and o-ring leaking. It's just above the axle seal on the left side, and makes it look like the axle seal is leaking. A little silicone sealer on the o-ring fixed mine!

 

Sounds an o-ring leak to me too! Take another look or replace it to see if it will make a difference.

 

Wasn't there a TSB about a black-colored IFS vent and a white-colored IFS vent fitting, meaning the little press-in fitting that the vent hose attaches to, where one was for mineral oil and one for synthetic oils? Something about the fitting sealing o-ring on one or the other being dissolved by synthetic lubes?

 

The leak was at the vent fitting. Thanks for the help. No more leak.