Rear Diff Smells like a Sewer PLUS: ID these diff parts???

[wired1000]

Pulled open my rear diff (standard m1009 gov lock I think). ...I had a previous thread where I asked about the howling sound it was making.

Anyway, opened 'er up... and nearly vomited. As the old oil came out, it was accompanied by a smell like the rankest of sewers. Anyone who's done plumbing will know what I mean... OMG it was HORRIBLE.

While I expect a rear end to smell like that, depending on diet... (harr harr), the rear diff took me by surprise... I never imagined it could be so bad.

Also, inside, stuck to the magnet, was a big old clump of metal shavings. Maybe like a quarter cup of them. Included was two big chunks of gear teeth and a couple pins and a spring. See picture...

Refilled with new oil and gave her a test drive just in case some new oil would solve the problem, even temporarily... but no dice... the howling persists.

My questions, though, are is smell something that happens? Or is something really F-ed?? Also, what do you figure isn't working now that these pins and that spring are missing?

 

[EODTECH90]

as far as exactly what those parts are not sure, but my step dad had a '98 with 97 body style GMC Siera 1500 ext cab 2wd with 5.7 and auto trans, he had howling coming from the rear end and the chevy dealer put new "carrier bearings" in it if i remember correctly

 

[EODTECH90]

almost forgot, if you have that, coming out of your diff then its bad, also on the oil smell thing, all oil has whats called "base stock" and an "additive pakage" in it
base stock=the oil itself the majority of substance in the bottle
Additive package= stuff put into the oil to make the oil actually work better. as in anti foaming agents, anti shearing agents, stuff like that
when you change oil you are really changing the additive package as well as removing the moisture, metal deposits into the oil gunk from the engine etc..
the degradation of oil over over time and not changing it as well as the excess heat produced by the bad components probably contributed greatly to the smell, at least if i remember right from AIT

 

[DokWatson]

You found a half cup of metal shavings, and several big pieces of junk, filled it up and decided to see it would magically fix itself? Time for a new differential, since the pieces you found are whats supposed to be holding it together.

 

[bushhawg73]

I had a 87 chevy and I broke the rear end. I ordered new gears and installed them, who needs to shim it, broke three sets of ring and pinion gears and finally destroyed the carrier. The roar, whine or howl sound is probably the gear set up. Someone with a dial indicator and some experience would be a great help in the repair. As far as the smell, gear oil has a special smell but you describe yours and toxic so I do not know.

 

[rickf]

Those are the remains of the Gov-lock. It will eventually shed bigger parts which will lodge in the ring gear and explode the differential. Why on earth did you find chunks and then put it back together?????


Rick

 

[wikallen]

Looks like the pins for the locking mechanism and cam. Question is, where is the rest of the cam and locking mechanism. Bad smell, howling, broken Gov-lock parts. You need to rebuild it. It will not be lasting much longer.

 

[idM1028]

Yay! Time bomb 10-bolts! Seriously though, probably one of the worst axles made by GM. Usually its not a matter of "if" they'll go bang, but "when". I could bore you with tales of said axles going bang, but. . . You could get the thing rebuilt, but a potentially easier and cheaper solution might be to go find a similar year 3/4 or 1 ton truck with the 9.5" 14-bolt in a junkyard. Should bolt right in, but double check your wheel pattern, brakes, suspension mounting points, and gear ratio. Probably wouldn't be a bad idea to check the U-joint too. That's what dad did when his went bang. Granted, I think his gear ratio was 3.73 which is probably easier to find than 3.08.

 

[Jersey4x4]

Just go back a few years and get a 12 bolt Chevy blazer rear and bolt it in. Brakes, lines, e-brake are all the same and they even had them with 3.08 gears. Only difference is the U-joint, You will need a conversion joint because the yoke is smaller by about .040 on the later model to the early model but all auto parts stores will have this as it was used in the 1980 and 1981 model C/K series trucks from the factory. As for the smell and the parts, Smell is normal for a diff that is going to burn up from pinion bearing wirring and the parts will not be needed if you swap out the rear and you may even find one with a locker in it.

 

[wired1000]

I bought a NOS rear axle (drum to drum) and had a shop put it in. Got about a mile down the road and it started making these HORRIBLE grinding sounds and the truck didn't want to move. Pulled over and the rear brakes (initial suspect) were not hot, but the pumpkin was hot as blazes. Had it towed to a different shop as the first one did not offer any warranty (not their part, I provided it) and I suspect that they did not fill the axle with oil before installing it and want to preclude them from lying about it.

Not even sure what to do at this point... the new axle was $250, plus $350 shipping, $300 to install. WTF. WTF WTF WTF. It's tempting to just scrap the stupid thing. Have the new one rebuilt? I dunno. Really upsetting.

 

[wired1000]

Maybe I'll pull the rear driveshaft and run front wheel drive til that axle goes out.

 

[indy4x4fab]

The "THE GOV BOMB" strikes again i see.

i have a spare open diff for that axle ill sell or trade it to u.

 

[Recovry4x4]

You are operating a 25yr old truck with an unknown history and no place to plug in a omputer. Now you are going to take it to an auto repair facility to have it worked on?
What I'm going to say will sound harsh but I mean it constructively. Now is the time to either learn how to do it yourself or lease something a little (lot) newer. If you told the shop to "Install It" that is likely what they did. Did you tell them to check or fill it with gear oil? If you didn't, it's likely that they didn't. Computers have really dumbed down the auto industry. With no place to lug in a computer, todays techs can't diagnose a problem. If you doubt me on that, go to an auto parts store when the power is out. I can go in mine and walk out with parts because the old codger parts guy can use a parts catalog and he can also make change. He is an extreme exception, not the rule. The counter parts guys are almost extinct.

 

[rickf]

Why would ANY shop install a NEW differential and not check the fluid! I mean it is NEW, as in never used as in NEVER filled. That does not fall under warranty, that falls under stupidity or incompetence. Your choice. They should be held liable.

Rick

 

[wired1000]

Jury is still out as to whether fluid was added or not. I generally do work myself, but there are some things I do not have the tools or the 400 lb lifting power to accomplish on my own, so I get a shop to do it.

 

[rickf]

Pulling the rear drive shaft will not help. The axles are still turning the differential.

 

[indy4x4fab]

And plus you can possible do damage to the t-case, part time cases are meant to be a part time use, not full wheel drive or all wheel drive. I know the np205 is a beefy case but, I wouldn't trust it in a front wheel drive app.

 

[wired1000]

 

[indy4x4fab]

Now we have limped trucks home from 4 wheeling on just front wheel drive with a np205 and they did just fine but I wouldnt true it much more then, a "get me home then fix it."

 

[wired1000]

Good to know. I'm just praying that the new axle wasn't damaged too much by whatever the **** it was that went wrong (mis-aligned? no oil?) It sounded fine for the first mile or so, then started with all the crazy nasty noises. I don't plan to do much 4-wheeling or towing, so once I can get it to work it should be OK for a while. If you want something done right, you have to do it yourself I guess. Wish I got paid $80/hr to f- up other people's cars....