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2002 gmc envoy_slt
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Discussion Starter #1 (Edited)
02 Envoy with 114k on the clock is pushing fluid out the pinion seal.
It also has a werring or wine sound after it gets warmed up kind of difficult to locate exactly where it comes from.

I changed the fluid with standard issue GM lube and its probably due for a change.

I need to check the fluid level to see where that stands, the fluid is on the body of the truck and doesn't puddle on the floor.

How hard is it to replace the seal.

Any thoughts as to how to find the cause of the noise.

Thanks!
 

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2003 chevy trailblazer_ls
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sounds like the rear ends toast if its whining and leaking out the pinion, to replace the pinion seal you need to pull both axles the carrier and all shims and then unbolt the pinion and take it out the rear then replace seal and get a new squash sleeve to put the correct preload on the pinion and then replace carrier. not a easy job and a lot of things to check with preloads and adjustments for the gears meshing correctly.

-Joel

I believe these rear ends use a squash sleeve..... some one else might now more.

PS:and these are not all the steps for this job just a quick summary.
 

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You can pay a shop $500-1000 to do that work, or get a junkyard axle with fewer miles and swap it yourself for $400 or so. Depending on your DIY skills. Pinion gear diff work needs a lot of experience to do properly, and to end up with no noise. Call a couple of local independent driveline shops to get quotes.
 

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Unless I'm missing something, you can replace the pinion seal by removing the pinion yoke, removing the old seal, and installing the new seal.

There are torque specs and procedures to be followed, and an inch pound torque wrench is needed, but removal of the axles is only needed if the ring and pinion are being removed.

Am I wrong? :confused:

That is, if the rear end isn't toast.
 

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Awww, you're right. I was thinking pinion BEARING, not the seal. If you tighten the nut too much, and exceed the torque reading obtained before disassembly, then you have to replace the crush sleeve and THAT requires everything to come out of the housing. But fixing the whine could be any of the bearings in there - a reasonably complex job. A friend just paid $1200 to do all the bearings in his Astro van's rear end plus one new axle shaft.
 

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ya in my earlier post i was thinking the pinion bearings also because off the whining plus like the roadie stated that if you go past the correct torque on the crush sleeve you have to replace that which is involved with taking the whole rear end out.

--joel
 

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The guys above are right on the money. Seal is easy but won't fix your noise problem.

Also check the breather vent. If plugged it can blow seals!
Did you ever go through hub-deep water? Could also be part of the problem.

Pull the cover and check/change the oil. Factory or full syn like Amsoil is best.
 

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My understanding and experience is that if you loosen the pinion nut, you MUST replace the crush sleeve and set the preload again. To properly set the preload, the carrier must be out (because you measure the force needed to rotate the pinion, and that force is created by pressing the bearings into their races with great force, and if you have the mass of the carrier and the axles, you'll never get a correct reading), which means the axles must be out. Lots of work, and if you are going to have to do all that, you should replace the bearings and races. Not worth it at all.

When I had a problem with the pinion bearing on my 03 Envoy, I simply replaced the entire differential. Took my son and I about 5 hours, if I recall correctly. Not really a bad job. Just time consuming. You'll want a transmission jack to help drop the old one out and lift the new one in, but other than that it's just hand tools. You can use a floor jack, but the balancing act gets to be dicy.

If you replace the diff, think about getting one with a G80, and if you are going to be doing any stressful stuff, think about getting the larger differential, 8.5" I think. rather than the 8.0" unit.
 

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Discussion Starter #9
Thanks for all the advise!

The noise is not really loud ... yet.... I was hoping that it might be one of the axle bearings, but not sure how to tell if they are the problem or not.

By the way the rear brake dust shields are gone .. rotted off... Thanks GM... the first vehicle I ever owned to have that happen! I was looking to replace the shields if it turned out to be an axle bearing.

Never been through high water but have trudged through high snow.

I've had to replaced the front diff seals, I guess GM doesn't expect these vehicles to last more than 100K.

Years ago I had an issue with a different vehicle with carrier bearings which wasn't hard to fix, I took out the ring assembly and had new bearings pressed on and then reinstalled it. That noise was loud and in the center of the car.

This noise is not that loud, it's defiantly from the rear and hard to determine which side or if it's from the center. The sound is higher pitched than the bearing noise I repaired in the past that was more of a rumble. Obvious in that case when you looked at the race and the bearing on one side of the carrier.

Never replaced a pinion seal before, thought that all I had to do was remove the nut that holds the drive shaft assy on replace the seal and reassemble.
The crush sleeve has me concerned.... without a parts breakdown I don't quite understand the significance.

Maybe I'm better off getting another G80 rear from the junk yard and replacing the entire unit.. that would have to wait till its warmer and my son is home from college.
 

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In my opinion you are better off replacing the entire differential assembly.

On my Envoy, the backing plates were totally rotted, and a bonus to getting a boneyard differential was that it had great backing plates. When you start adding up the price of the parts you will need (pinion seal, crush sleeve, pinion bearings, axle seals, maybe axle bearings), and perhaps some special tools, (like an inch-pound torque wrench with a dial indicator and a slap hammer with the proper attachment for the end to remove the axle bearings, and a seal puller if you don't have one already), you will find that simply replacing the entire differential is a wise choice and even economical choice.

Just my thoughts.
 

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Is it one the diff bearings, ring gear to pinion, spider gear, or one of the wheel bearings making noise? You might want to jack up the rear and run it when warm. See if you can locate where the noise is coming from. Noises to all of us is not the same. Wheel bearings are somewhat cheap.
 

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Discussion Starter #13
Checked out your link ...What a Mess! Never saw one puke like that!

I need to get a price on the shields, axle bearings and seals for cost and verify that the problem is an axle bearing, if not it looks like the bang for the buck goes to replacing the unit.

The key seems to me is getting a young replacement.

The noise is there, but on the highway it's barely noticeable, really can't even hear it when the road is wet. It's a pretty quiet ride thats why I guess it's noticeable.

I checked today to see how much fluid it's pushing out from the pinion seal.. looks worse than it is.. its damp around the flange and the spatter is not real bad on the body.

I verified that it has a 3.42 locking differential (based on the window sticker)

Thanks for your help. I'll update this thread when I get a direction and go with it.
 

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G80 tech?

Hi all, I was wondering what exactly a G80 is, what does it look like, what are the benefits of having one, and what do they cost? I have seen so many posts where members have them listed in their mods tag but i cant find anything about them.
 

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Welcome. What did you find using "search"? It's really been discussed well for the last five years or so.

Quickly, they pretty essential for offroading, can cost $500-1000 if you add one later.
 

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Discussion Starter #16
Back a year latter.

Thanks for all the advise!

The noise is not really loud ... yet.... I was hoping that it might be one of the axle bearings, but not sure how to tell if they are the problem or not.

By the way the rear brake dust shields are gone .. rotted off... Thanks GM... the first vehicle I ever owned to have that happen! I was looking to replace the shields if it turned out to be an axle bearing.

Never been through high water but have trudged through high snow.

I've had to replaced the front diff seals, I guess GM doesn't expect these vehicles to last more than 100K.

Years ago I had an issue with a different vehicle with carrier bearings which wasn't hard to fix, I took out the ring assembly and had new bearings pressed on and then reinstalled it. That noise was loud and in the center of the car.

This noise is not that loud, it's defiantly from the rear and hard to determine which side or if it's from the center. The sound is higher pitched than the bearing noise I repaired in the past that was more of a rumble. Obvious in that case when you looked at the race and the bearing on one side of the carrier.

Never replaced a pinion seal before, thought that all I had to do was remove the nut that holds the drive shaft assy on replace the seal and reassemble.
The crush sleeve has me concerned.... without a parts breakdown I don't quite understand the significance.

Maybe I'm better off getting another G80 rear from the junk yard and replacing the entire unit.. that would have to wait till its warmer and my son is home from college.
One year latter.....Well I didn't replace the entire unit. I replaced the dust shields, axle bearings and the seals. The noise is still there and not much louder than it was a year ago. I have narrowed it down to the pinion bearing, the seal is still leaking, a little more than a year ago.

So I'm thinking I can replace the pinion bearing without too much fuss. My thinking is if I replace the bearing and give it the preload as per specs everything else should be the same. What I mean is I'm not replacing the carrier bearings or the ring and the pinion just the bearing. So in theory the same parts with the exception of the pinion bearing should not need mean a realignment of the entire diff.

So I'm here looking for those who know more about diff repair to tell me what they think.
The bearing and seal are cheap < $40 . The parts I replaced didn't cost not much either, maybe $75.00.

Thanks!
 

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Replacing the pinion bearing and seal are not the worst jobs one could do. They are easier than trying to set new gears or change the carrier for a locker, etc., as the shim settings should stay the same. You will have to completely disassemble the rear axle components to get at the pinion bearings (there are two, an external and internal). You could try to just replace the external bearing and see what happens, or you could try to replace both bearings but not the internal bearing race (usually shimmed for pinion depth) as the shims are generally destroyed when driving out the inner race.

The steps are:

Pull brake hardware
Pull C-clips
Pull axle shafts out far enough to remove the carrier
Remove the pinion nut and yoke (do this while the carrier is still in place)
MARK the carrier bearing caps very carefully -- they MUST go back in exactly the same way as they came off and are not swappable or replaceable
Remove the carrier bearing caps
Pull the entire carrier assembly, paying attention to any shims/spacers that may be in place under or over the carrier bearings so they can be reinstalled in the exact same way
Slide out the pinion
Remove the outer bearing -- watch the shims and make sure they go back in the precise order
Remove the inner bearing from the pinion (this bearing is pressed on and requires a shop press and a bearing separator plate, or a specialty clamshell bearing tool for pulling differential bearings) watch shims and replace in the exact order
Drive out the forward race -- if shimmed (not typical) replace with new shims in the exact same size
Drive out the rear race -- if shimmed (typical) replace with new shims in the exact same size
Replace both races and shims -- fully seat (this is done with a brass drift punch and a hammer or a specialty bearing and seal driver tool
Press on new inner pinion bearing
Slide pinion into its bore, replace outer bearing
(This step is optional, but recommended!)
Replace bearings on the carrier -- these are pressed on and may be shimmed. This takes specialty tools, either a bearing separator plate and a puller or the specialty clamshell bearing tool. Take care with shims and replace exactly as before!
Press on new bearings with a shop press
Replace carrier into housing (it WILL fit very snugly but typically no case spreader will be needed)
Replace carrier caps, torque to specs
Adjust pre-load on pinion via torque spec or crush collar
Test backlash on ring gear (requires a dial indicator and stand)
Test pinion pre-load (requires dial-type inch pound torque wrench)
If all is good, install the pinion seal and re-torque the yoke. (This step can happen before you set pinion pre-load as long as you get everything right the first time, if not, you will need to remove the seal and replace it with a new one)
Slide axle shafts back in place
Replace C-clips
Inspect work
Install rear cover and fill with oil -- I recommend Amsoil synthetic gear lube
 

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Discussion Starter #18
Thank you

Very thorough description of the process and the details that need special attention.

My guess is that the inner/outer question might be answered once the pinion is removed and inspected carefully.

I really appreciate your taking the time to respond with such detail!

Question; Any chance the preload on the bearing has changed and is causing the noise due to it being too loose?
 

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Question; Any chance the preload on the bearing has changed and is causing the noise due to it being too loose?

Yes. Try resetting the preload on the pinion before tearing the axle apart. You may get lucky.

Also, the shims are between the pinion gear and the inner bearing (not the race/housing) on our rear ends (both types) you can replace the bearings/races without destroying the shim.
 
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