Front Axle Seals Leaking On '01 2500 Hd

Fortune50 · November 25, 2007

Just would like to know some tips on replacing the front diff axle seals on my '01 Sierra 2500 HD 4x4. The driver's is a bit leakier than the passenger side. Does the diff have to come down? Anyone with a link or a how-to on replacing these?

jwhjr · November 25, 2007

I had mine replaced under warranty so I can't help you on the how to, but I was wondering how common this is? I've seen quite a few posts about the front axle leaking and I know of a few people who have had the issue themselves.

Fortune50 · November 26, 2007

I had mine replaced under warranty so I can't help you on the how to, but I was wondering how common this is? I've seen quite a few posts about the front axle leaking and I know of a few people who have had the issue themselves.

I do believe it's actually a standard option on GM 4x4 IFS models, lol. My buddy's '02 Tahoe Z71 is the same way.

Can anyone give some advice or more info on fixing this problem?

BC2500HD · November 26, 2007

Try removing the diff vent tube valve on the top of the vent. Unless you do a lot of deep water 4x4ing. Sometimes ti gets dirt in it and you diff build pressure and the seals can leak.

Shu · December 1, 2007

How common of a problem is this really? Mine just started leaking on my 2005 1500 4x4 and I have about 58000 miles. There seem to be a lot of people asking about this problem, so to me it seems pretty common, but no one has given details on what it entails to replace these seals. It appears you should be able to just unbolt the half shafts from the front differential shafts and move the half shafts and CV's out of the way. Then I assume the axle ends are bolted onto the axles like the yolk on the rear differential is on the pinion????? If so, wouldn't you just then remove the nut and pull the yolk? Is the yolk a press fit or does it just slide off? Any details on exactly how one could do this procedure at home would be greatly helpful. Since mine is out of warranty and I have been wrenching on cars for over 20 years, I would prefer to do it myself and save a little money this Chistmas season. Also, since this sounds like a common problem, are there any aftermarket seals that are better than the OEM replacements? Or any tips on how to prolong the seal life? Also what gear oil does the front take?

BC2500HD · December 1, 2007

Try removing the diff vent tube valve on the top of the vent. Unless you do a lot of deep water 4x4ing. Sometimes ti gets dirt in it and you diff build pressure and the seals can leak.

I had this problem 3 times each side on my 97 Z/71, all replaced by the dealer. I finally got fed up and pulled the diff out and took it to a diff shop and had them look through the diff just to make sure all was OK inside. (after all the leaks I wanted to be sure all the bearings etc... were OK) It turned out everything was good. But they told me to remove the diff vent valve to make sure the pressure in the diff could escape. they said sometimes dirt causes this 2 cent part to clog. After that no more leaks. It doesn't hurt to try. IT'S FREE

Fortune50 · December 2, 2007

Well, ok then I'll pull that vent tube "breather" thingy off when I get the chance and see what happens-hopefully that'll take care of it.

I did buy a factory service manual from eBay. It says that the CV axleshaft comes off to get to the left seal.

So, this appears to be the steps to take to replace the left axle shaft seal on the diff:

Jack up the front left tire and remove it.

Remove the center hub cover, insert a screwdriver or drift into the brake rotor thru an access hole thru the caliper to keep it from turning, and loosen & remove the CV axleshaft's nut & washer.

Remove the 6 bolts holding the CV axleshaft to the inner axle, remove the stabilizer bar endlink from the lower control arm, and then drop the CV axle out thru the lower control arm w/o damaging the CV joint rubber boot covers.

Next is to take a slide hammer and then attach to it a special tool which bolts onto the inner shaft's flange, then pull the shaft out of the diff.

Then with another style of slide hammer, attach to it another special tool to allow removal of the axle seal and the inner bearing (if its bad).

Then for installation, use a special bearing installer tool to install a new bearing, then use one of the special seal installer tools (one for 8.25" diffs, the other for 9.25" diffs) to install the axle seal

Install the inner shaft into the diff and fully seat it by tapping it with a soft mallet

Install the CV driveshaft while taking care that the rubber boots aren't damaged in the process, and that the steering knuckle and wheel drive shaft splines & threads are free of any grease, dirt, rust, etc.

Install the CV axle into the splines of the hub and install the washer, and then install a NEW axle nut to hold it in place-don't tighten it yet, DO NOT re-use the old axle nut.

Then reinstall the flange bolts to connect the inner shaft to the outer CV axle shaft. Install a drift or screwdriver thru the rotor as you did before and then tighten the flange bolts to 58 lb-ft. Then tighten the hub nut to 155 lb-ft.

The rest is the reverse of the removal. Tighten the stabilizer bar endlink to 81 in-lbs. Tighten the wheel lugnuts to 140 lb-ft. INspect the fluid level in the diff if any is needed, add to it. Should fill it to the top of the fill hole.

Hope this helps w/ those inquring about the left (driver's side) seal/bearing replacement.

The right side is more involved yet as you have to disconnect the inner axle shaft's housing off the IFS carrier & frame and the remove the clutch fork componants (about 10 pieces to it) in order to get the inner shaft to come out so you can get to the seal/bearing.

John Dillinger · December 2, 2007

03 2500HD - changed front differential first time yesterday at 70K. Oil was black/burnt and magnet had an inch of shavings attached & oil 1/2 quart low. Oil leaks down and catches on skid plate and oil never makes it to the ground....so you can't tell it leaks by seeing oil spot on ground.

Sounds like a common problem.

I plan to check oil more frequently and keep oil topped off.

Fortune50 · December 3, 2007

03 2500HD - changed front differential first time yesterday at 70K. Oil was black/burnt and magnet had an inch of shavings attached & oil 1/2 quart low. Oil leaks down and catches on skid plate and oil never makes it to the ground....so you can't tell it leaks by seeing oil spot on ground.

Sounds like a common problem.

I plan to check oil more frequently and keep oil topped off.

Yeah, when I changed my buddy's front diff oil for the first time on his '02 Tahoe about 3 yrs ago, it had around 45K on it and it was dirty & full of metal shavings on the drain plug. Since then I've changed it about 4 times to try and keep it fresh. When I changed my front diff oil on my '01 GMC, it looked pretty good at 127K mi, must've gotten at least some regular maintanance.

ballon78 · December 4, 2007

I've had many of the blazer, s10 ZR2 and the same thing. Gm replaced twice with oemseals and they still leaked then, my dad and i replaced them with napa seals and the leak stoped. I think that gm seals are to hard of a rubber or somthing, i hope i don't have another problem as i just bought a nbs siverado!!!