Rear Differential

[Unit505]

Okay, I've been in this 2000 Sierra for about 4 months now and after running the vin and carefully reading the factory window sticker, which was in the glove box, nothing mentions an LS or eaton locker. I know the truck has a 3:42 gear and I was sure that I had an open diff. Spun the right rear tire many times as there is a spot that holds water like a lake leaving out of the neighborhood and never any hint of the rear locking up. My 2002 and 2003 will lock up when one tire spins and they both have RPO codes for the eaton locker. The 2000 never has and does not have an RPO code for the eaton. Last night, I was in a mood and punched it on dry blacktop and lit up both rear tires and got a bit sideways on me. Let off for a sec and mailed it again and again, lit up both rear tires. I was like WOW! Now I'm wondering WTH? I know the truck was wrecked by the previous owner and I'm wondering now if it he may have had the differential replaced. With my other two trucks, you can feel the differential lock up after a brief spin. Last night, the 2000 just spun both tires without that lockup grab or feeling. I'm at a loss. I really need a locker in it for my trips to the hunting grounds, so I'm guessing that my only option is to pull the diff cover and see whats in there? The truck is an SLT with factory hd towing package if that helps. Are there any external markings that would help me identify what the diff is?

[Nanotech Environmental]

On some years, (maybe all?) there is a sticker in the glove box with all the option codes your truck has. If the sticker is there, it would have G80 somewhere in the list, if it had a factory locker.

The only way to know for sure what you have is to pull the diff cover.

 

IMO, a truetrac is a way better unit than the Eaton timebomb. The Eaton is an amazingly poor design that should have never went past the drawing board stage. Asking hardend metal parts to slam-lock like that is just begging for broken pieces....

Plus, the truetrac can be bought for a lot less $$

[Unit505]

No G80 on the rpo list. I don't personally like the eaton, but it works on my other two trucks and I'm very easy if I know that I'm going to spin the tires. I'll have to research the truetrack. Thanks!

[2timeGMC]

Hi, Please help. My 2009 GMC Sierra - 4WD first started making a loud boom when backing up occasionally. Very scary. Like you just backed into a wall. Then starts acting normal. Now the differential( rear end )completely slips making this grinding noise. The engine revs up, so have to let off the gas. When the RPM's go back down the rear end would engage again. The problem kept getting worse. Now having to drive it with front wheel drive (4 wheel high) . Is anyone have this problem?

Thanks

Jerry

[00Silverado4x4]

Jerry, it sounds more like your transfer case has a problem. I'd get it to a shop and have them look it over. I personally had to replace my transfer case as the one that was on it when I bought it earlier this year had all kinds of problems.