Pinion and Axle Seal Replacement

[MarshMarlowe]

I recently brought my wife's 2012 LS 2WD 5.3 Tahoe in to the dealer for the Takata Airbag recall. They did their multi-point inspection, and noted the Pinion Seal and Axle Seal was leaking

Their repair quotes were typically expensive for dealer rates. I've been researching how to repair this myself, and have a few questions

See Photos

Rear End is a 14 bolt, 3.42 (opt GU6)

Are there known correct size pinion / axle seals for this axle?

What is the correct size socket for the Pinion Seal for this rear end?

Is it typical for just one side of the axle to leak? The leak doesn't look bad... Does it really need attention right now?

I don't have a lot of good access to the rear end diff cover plate. Is replacing the axle seal going to be more trouble than it's worth versus paying a shop to do this job?

Thanks

 

[swathdiver]

I recently brought my wife's 2012 LS 2WD 5.3 Tahoe in to the dealer for the Takata Airbag recall. They did their multi-point inspection, and noted the Pinion Seal and Axle Seal was leaking

Their repair quotes were typically expensive for dealer rates. I've been researching how to repair this myself, and have a few questions

See Photos

Rear End is a 14 bolt, 3.42 (opt GU6)

Are there known correct size pinion / axle seals for this axle?

What is the correct size socket for the Pinion Seal for this rear end?

Is it typical for just one side of the axle to leak? The leak doesn't look bad... Does it really need attention right now?

I don't have a lot of good access to the rear end diff cover plate. Is replacing the axle seal going to be more trouble than it's worth versus paying a shop to do this job?

Thanks

Looks like a typical 10-Bolt 8.6" rear axle to me. 14 bolts and Tahoes had 6.2 engines in 2008 and 2009 only AFAIK.

Anyhow, the axle shafts have to come out to replace the seals and the C-Clips can be a pain to get out. The brakes have to come off to get to the axle shafts. You also have to remove the pin in the center chunk, hope the locking screw doesn't break in half and hope the center section doesn't rotate too far to throw off the orientation of everything to where you have to spin the diff in 300 different ways to get everything aligned up again. The pinion has a crush sleeve but people cheat with an impact gun, scribing a line on the nut and housing and then when putting it back together, tightening it to the scribe mark and not torqueing to spec.

The leaking axle seals will eventually take out the parking brake shoes and maybe the brake pads if it gets worse. If you keep the fluid level in spec, you can kick the can down the road a while. If she runs low or out of fluid, a complete overhaul would be in your immediate future.

 

[swathdiver]

Axle Seals are 291-315/12471686.

The Pinion Seal is 26064029.

You can use an OTC 4508 to pull the seals out.

You would use a J-38694 to install the pinion seal.

You would use a J-21128 to install the axle shaft seal.

Lots of DIYers use a block of 2x4 as a seal driver.

 

[MarshMarlowe]

Looks like a typical 10-Bolt 8.6" rear axle to me. 14 bolts and Tahoes had 6.2 engines in 2008 and 2009 only AFAIK.

Anyhow, the axle shafts have to come out to replace the seals and the C-Clips can be a pain to get out. The brakes have to come off to get to the axle shafts. You also have to remove the pin in the center chunk, hope the locking screw doesn't break in half and hope the center section doesn't rotate too far to throw off the orientation of everything to where you have to spin the diff in 300 different ways to get everything aligned up again. The pinion has a crush sleeve but people cheat with an impact gun, scribing a line on the nut and housing and then when putting it back together, tightening it to the scribe mark and not torqueing to spec.

The leaking axle seals will eventually take out the parking brake shoes and maybe the brake pads if it gets worse. If you keep the fluid level in spec, you can kick the can down the road a while. If she runs low or out of fluid, a complete overhaul would be in your immediate future.

Thanks - sounds like it might turn into a real headache attempting this myself

The code for the rear end on the build sheet is GU6 3.42 - were those made in 10 bolt?

Is scribing the Pinion nut / stud poor practice in lieu of torquing to spec?

 

[swathdiver]

Thanks - sounds like it might turn into a real headache attempting this myself

The code for the rear end on the build sheet is GU6 3.42 - were those made in 10 bolt?

Is scribing the Pinion nut / stud poor practice in lieu of torquing to spec?

GU6 only denotes the axle ratio, not the differential used. 4x4s and RWD models with the 6.2 engine got the AXN 14-bolt axle. They would still have the same GU6 gear ratio.

It is a poor practice but it works and saves time. A fair amount of time.

If things don't go wrong, it's all pretty much straight forward but if they do, it'll add many hours to the repair or days if you do not have the right tools. I got lucky and didn't have the locking screw break on the differential pin but moved it too much and spent hours trying to get everything aligned to put it back together. The seal took 5 minutes. Going to the store right before closing to buy pry bars took 45 minutes and another couple of hours to gain a 64th of an inch to get the last c-clip in.

I'm about to embark on this adventure again with my new axle!

 

[Just Fishing]

I did the scribe and thread count trick when i did my S10, it worked great.
I also replaced the bearings while I had it apart, but I found slop in the pinion and the rear axled had some up and down slop.

Replacing it with quality stuff + the scribe trick didn't burn me in my "rear end", I got a good 80 or 100k after that, and it's still kicking.

 

[Doubeleive]

like mentioned already the axle leak will take out the brake, the bottom line here is if the pinion is not done correctly it will leak again or go bad.
typical shop price for the pinion is around $650-800, doing the axle seal should basically be thrown in since all they have to do in the process is fully remove the shaft and replace the seal.
not trying to discourage you just saying if not done correctly the 1st time you might find yourself under it again. the parts are cheap enough it's the labor they get you for.

 

[MarshMarlowe]

I found a shop willing to do all 3 seals for $450 w/ fluid. The shop rep tells me the Pinion and Axle bearings in the 3.42 and/or 10 bolt? Rear are known for failing which leads to the leaking seals. $200 more to replace the bearings, and this includes carrier bearings

$650 versus fumbling my way through this and potentially doing it wrong...

I think I'll go with the shop. Thanks everyone, great forum

 

[Doubeleive]

I found a shop willing to do all 3 seals for $450 w/ fluid. The shop rep tells me the Pinion and Axle bearings in the 3.42 and/or 10 bolt? Rear are known for failing which leads to the leaking seals. $200 more to replace the bearings, and this includes carrier bearings

$650 versus fumbling my way through this and potentially doing it wrong...

I think I'll go with the shop. Thanks everyone, great forum

I think I had my pricing memory wrong, your price quote is probably fair for all of that.

 

[swathdiver]

I found a shop willing to do all 3 seals for $450 w/ fluid. The shop rep tells me the Pinion and Axle bearings in the 3.42 and/or 10 bolt? Rear are known for failing which leads to the leaking seals. $200 more to replace the bearings, and this includes carrier bearings

$650 versus fumbling my way through this and potentially doing it wrong...

I think I'll go with the shop. Thanks everyone, great forum

Keep us posted. We see a pinion bearing once in a while, can't remember the last axle bearing that went out on here or the latter for that matter!