1996 4door 4.3 4x4 148k miles
Driving down the road at about 20mph. BAM!!!! Rear end explodes. I limp it about a mile home. Take cover off and chunks fall out. Appears to be just ring and pinion. It just had the pinion seal replaced. I'm guessing the shop didn't torque the pinion back down considering it was less than 30 miles ago.

So what's my next step? Ill call dealer and give my vin so I know what my gears are. Unless they are all the same or something. Banging my head off the wall. Kinda depressed. What else should I look for as far as damage? Is this typical or possible linked to the pinion seal replacement?

 

Talk to the place that replaced the seal. Quite possible the pinion nut was over or under torqued. If that's the case, they should take care of it.

 

Thanks. I called them. I told them about pinion but being torqued incorrectly. They basically don't care.

 

Does your State have a BAR, (Bureau of Automotive Regulation)? If so, you might give them a call, either that or an attorney. You might have to have it looked at by another shop to confirm the problem and possible cause.

EDIT: Before the pinion nut is loosened, rolling torque must be checked. When the nut is reinstalled it must be tightened to achieve the same rolling torque. If it's too loose, the pinion shaft will wobble around and destroy the pinion bearing and then the ring gear. If it's too tight, it will also destroy the pinion bearing and the pinion gear will eat the ring gear.

 

I live in CA so I am sure we have something like the BAR

The description you posted sounds like exactly what happened. I mentioned that to him and he laughed at me and said his guys don't make those mistakes. But either way I'm calling tomorrow and telling him they need to fix it. From what I've read the spider gears would have gone if pinion was not the issues.

Also the part about the pinion nut, is that a quote from a manual or just your accurate description?

 

Check with your secretary of State office, they can tell you what steps you need to take.

It is paraphrased from the GM shop manual. That is the procedure whenever the pinion nut is removed. It guarantees that preload is back where it was before disassembly to prevent what happened to yours. Another option is replace the crush washer and set up the differential from "scratch", (far more time consuming). You are correct about the side gears and side bearings.

 

Well the shop has had my blazer since last Thursday. They said they would fix it at their cost. They are replacing the entire rearend. Apparently California is fresh out if these rears and they had to get one from Oregon. Waiting for it to arrive and install

 

sounds like that shop guy is a douche and when theyre done id just leave and not pay, they owe u that cause they are the ones who messed it up. if they did their job and didnt make that mistake u wouldnt be in this situation.

 

As bright as an idea that is the shop is going to have his keys an address.They may not give him is keys back if he trys to walk out without paying.I agree the shop are the ones who screwed up and the owner of the vehicle shouldnt have to pay a dime.
I delt with a very similair issue some years back.The exact samething happened.The ring gear pin nut wasnt tightened all the way and it came out going into the gears of the rear end causing it to explode.Unfortunately I could not get the shop to pay for a new one.I ended up replacing the rearend myself out of my pocket.

 

Well I'm glad they're fixing it and paying for it. Hope it all goes smoothly for you.