99 chevy front differential seal

99chevy-ARMYMAN · 05-12-2009, 06:32 PM

I HAD MY LEFT FRONT DIFFERENTIAL SEAL LEAKING FOR SOME TIME NOW. FINALLY REPLACED THE SEAL AND NOTICED AFTER AN HOUR DRIVE THERE WAS STILL A SMALL LEAK.I BOUGHT THE SEAL FROM A DEALER.DOES ANYONE HAVE AANY IDEA WHAT COULD CAUSE THIS SEAL TO KEEP LEAKING?THE LEAK IS NOT AS BAD AS BEFORE I CHANGED IT.LEFT DRIVE AXLE.1999 CHEVY SILVERADO 3 DOOR 5.3 NEW BODY STYLE.HAS AROUND 140,000 MILES.

leolkfrm · 05-12-2009, 07:03 PM

welcome to the forum
did the old dry seal cut a grove in the shaft?

Erock80 · 05-12-2009, 07:33 PM

Yeah, check the shaft, make sure there's no debris, rust, grooves... Sometimes new parts can be defective... but for a seal though... idk. Possibly the shaft is bent? Maybe from an accident or off-roading/debris?

FaselZ71 · 05-12-2009, 07:52 PM

Now this may be a silly question but did you lube up the seal before you installed? Just like oil filters all seals should be prelubed before installation!! NEVER USE GREASE!!! Because grease and oil are 2 different bases and they cancel each other and will cause a leak!! Now if you use a oil based grease it will work but if you didn't prelube your axle seal then it'll leak garenteed!!!

99chevy-ARMYMAN · 05-20-2009, 09:53 AM

on the shaft there was a small grove about 1/2 inch in length just enough for the thumb nail to catch.

the truck has never been in an accident.the shaft appeard to be fine except for small grove.

i did lube the seal and shaft before i installed with front differential oil.

i think the small grove is my problem.should i sand down or replace shaft? its not deap at all.

NCroadracer · 05-20-2009, 07:37 PM

The groove could have caused it, though.. knowing those front diffs.. you should drain your fluid and check it for a high metallic content, which is indicative of a failing bearing. Very common in that diff.. the metallic content is abraisive to the seals and causes them to leak.. long before the front diff will make a notable growling noise.

the magnetic tip of the drain bolt will look like a grey afro if the carrier bearing are failing.

05-12-2009, 06:32 PM	#1
99chevy-ARMYMAN Junior Member Join Date: May 2009 Posts: 2	99 chevy front differential seal I HAD MY LEFT FRONT DIFFERENTIAL SEAL LEAKING FOR SOME TIME NOW. FINALLY REPLACED THE SEAL AND NOTICED AFTER AN HOUR DRIVE THERE WAS STILL A SMALL LEAK.I BOUGHT THE SEAL FROM A DEALER.DOES ANYONE HAVE AANY IDEA WHAT COULD CAUSE THIS SEAL TO KEEP LEAKING?THE LEAK IS NOT AS BAD AS BEFORE I CHANGED IT.LEFT DRIVE AXLE.1999 CHEVY SILVERADO 3 DOOR 5.3 NEW BODY STYLE.HAS AROUND 140,000 MILES.

05-12-2009, 07:03 PM	#2
leolkfrm Senior Member Join Date: Mar 2008 Location: N.Y. Posts: 4,300	welcome to the forum did the old dry seal cut a grove in the shaft? __________________ 4 wheels move the body 2 wheels move the soul B.W.A.I

05-12-2009, 07:52 PM	#4
FaselZ71 Senior Member Join Date: Oct 2008 Location: Northern Michigan Posts: 1,177	Now this may be a silly question but did you lube up the seal before you installed? Just like oil filters all seals should be prelubed before installation!! NEVER USE GREASE!!! Because grease and oil are 2 different bases and they cancel each other and will cause a leak!! Now if you use a oil based grease it will work but if you didn't prelube your axle seal then it'll leak garenteed!!! __________________ IT'S PEANUT BUTTER JELLY TIME!!! http://www.youtube.com/watch?v=s8MDNFaGfT4

05-20-2009, 09:53 AM	#5
99chevy-ARMYMAN Junior Member Join Date: May 2009 Posts: 2	on the shaft there was a small grove about 1/2 inch in length just enough for the thumb nail to catch. the truck has never been in an accident.the shaft appeard to be fine except for small grove. i did lube the seal and shaft before i installed with front differential oil. i think the small grove is my problem.should i sand down or replace shaft? its not deap at all. Last edited by bradrhale; 05-20-2009 at 11:33 AM. Reason: condensing posts

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05-12-2009, 07:33 PM	#3
Erock80 Senior Member Join Date: Oct 2008 Location: Rochester NY Posts: 104	Yeah, check the shaft, make sure there's no debris, rust, grooves... Sometimes new parts can be defective... but for a seal though... idk. Possibly the shaft is bent? Maybe from an accident or off-roading/debris?

05-20-2009, 07:37 PM	#6
NCroadracer Senior Member Join Date: Apr 2007 Posts: 295	The groove could have caused it, though.. knowing those front diffs.. you should drain your fluid and check it for a high metallic content, which is indicative of a failing bearing. Very common in that diff.. the metallic content is abraisive to the seals and causes them to leak.. long before the front diff will make a notable growling noise. the magnetic tip of the drain bolt will look like a grey afro if the carrier bearing are failing.

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