rear end troubles

[completetech]

I know nothing about rear ends on vehicles, except that they are there.

So anyhow I am hoping for a little guidance or help as to where to start.

1999 Astro AWD Cargo
176,000+
4.3 Vortec

One day the rear end felt a little funny, almost like a slip, sort of, and just at super slow speeds. Less then 30MPH. Thought no big deal. I will look and make sure everything is fine once I get home (at that point 75 miles away). However I only made it about 30-40 before a horrible squealing kind of grinding noise came from the back of the vehicle.

I stopped and checked and it appeared as though the rear end was leaking from the seal I had just replaced 2 months prior. So I had it towed back home. It sat for weeks, about 3 until I had enough time to replace the seal and the cover for the rear end.

I replaced both of them with out any issues. But then I filled it up with the recommended amount of rear end fluid. waited for a little while (30-60 minutes) then drive to the end of the street (at about 10-30 MPH). however the noise was still there.

Where would be a good place to start? I tried to bring it to the mechanic, however due to the fact of the exhaust exploding (I know, crazy, but it did. It looks like a m80 after it's went off) he is having a hard time finding the noise.

And to be honest I am not sure if it is worth it to fix the thing or not. My thing is there is so much money into the shelving and ladder rack, drawers, gate, rubber mat throughout I would like to keep it if I can or a mechanic can. Because the thing is I hate looking for new vehicles (new to me at least), since it is Winter here in Michigan, everything with 4x4 or AWD is through the roof and so that also makes a big difference. That and also trying to sell a van that I have no idea whats wrong with it also makes getting rid of it all that much more difficult also.


Thanks for reading this super long post, but I really wanted to give as much detail as possible. Although I may have been rambling on about unrelated things.

thanks again,
Nathan

[LiftedAWDAstro]

Sounds like the rear end ran low on oil and burned up one or both of the pinion bearings. When you replaced the pinion seal the first time, did you torque it down so the preload matched what was there before? Did you at least mark the nut to the pinion shaft so it went back to the correct location? If the answer is no, you most likely lost the outer pinion bearing due to loosening up and taking out the seal again. To fix it, you are gonna have to open it up, pull the axle shafts part way out, remove the carrier making sure the shims and bearing caps stay on the correct side, and remove the pinion completely. Now you need to inspect the gears themselves. If they are pitted, or have a weird wear mark, they are trashed. Now look at the pinion bearings. They must not have any pitting or score marks. If they do they are trashed. To replace them requires new bearings, a new crush sleeve, new seal, and an inch-pound torque wrench to properly torque the pinion nut down.

Might be cheaper to find a used rear axle with the correct gear ratio!

[completetech]

thanks for the reply.

However I am very lost. I dont work on rear ends that much. But it seems to me that just simply replacing the rear end cover and seal would not require all of the pulling out of the axle or any of the other items you mentioned. It was simply slow leaking a little fluid. So I replaced the seal. then filled. However my first "seal job" wasnt so great as it appeared to still be leaking a little so I replaced the rear end cover and the seal and used a bit more sealant this time. then tightened back down. I didnt use a torque wrench or anything but again I have only driven it very little a few hundred feet or so.

As far as checking those other things. Where do I start? I am more referring to reference material. I do have the little repair manual from AutoZone if that might help me. #-o

[MountainManJoe]

Lifted thought you meant a different seal. If it was only leaking a little bit, it's unlikely that caused any damage. Are you sure it's coming from the differential and not the brakes or anything else? I might try raising the van on block/jackstands, and have someone gently give it gas while you inspect. If the exhaust is too loud, maybe get that fixed first. You can't drive it until you fix your fuel problem anyway right.

[completetech]

Lifted thought you meant a different seal. If it was only leaking a little bit, it's unlikely that caused any damage. Are you sure it's coming from the differential and not the brakes or anything else? I might try raising the van on block/jackstands, and have someone gently give it gas while you inspect. If the exhaust is too loud, maybe get that fixed first. You can't drive it until you fix your fuel problem anyway right.

you mean the leaking? Yes I am sure it was leaking from there. The noise sounded like from bake there but I guess it could be the brakes also

[MountainManJoe]

I meant the sound. You're gonna have to hunt it down.

[doyoulikeithere]

If it turns out the axle will need work inside, and you pay a mechanic for that sorta stuff, you will probably find it cheaper to have him or her install a good axle from the pick n pull, rather than re-build the one you have.

[completetech]

Found a rear end from the local junk yard for $250... That seems pretty fair to me

[completetech]

however, I have been looking online and whatnot and it keeps saying to make sure you are ordering the right rear end based on the gear ratio... This will be the first time ever messing with a rear end so how do I tell what to get?

And I guess along those same lines if I'm going to be replacing it which of course I already know will be a lot easier. But what all would I be looking at as far as rebuilding it?

[MountainManJoe]

Did you find out what the sound was? At least jack up the rear and give the wheels a spin with your hand.

[completetech]

Not yet. I'm mostly as far as the rear end noise goes trying to get my ducks in a row

[completetech]

how do I tell what gear ratio I will need. I am being told as I have also done some looking around as well (here and internet) that there are 3 different ratios.

so how do I know what to look for at a junk yard?

[MountainManJoe]

I'm surprised we don't have a sticky for that in the REAR AXLE section (where your topic should be ). Allow me...
viewtopic.php?f=59&t=8111

[completetech]

thanks. I never knew that and didnt see that anywhere before..

[MountainManJoe]

My pleasure. Did you find where the sound was coming from?