2000 sierra 4wd rear posi question
 

so yesterday i was pullin away from the curb in 2wd and the right side rear was sittin in a buch a snow, and it just sat there spinnin. Trucks got about 87k on it i think, do these posi units give out or somethin? couldnt get the truck to move, had to put it in 4 wheel. any thoughts?

Brad

Re: 2000 sierra 4wd rear posi question
 

First off does it have the G80 option. Check the sticker in the glove box. Or if you got it used maybe the rear was changed at some time. It is possible that it needs a fluid change to "clean out" the clutch packs. The Eaton type of diffrential does have clutch packs and a lot of little parts that can get "gummed up"

Re: 2000 sierra 4wd rear posi question
 

Ok thanks, ill check the code, and my dad bought it new and then i bought it off him, so i kno the diff has never been touched. Ill check the code and get back.....

thanks again

brad

Re: 2000 sierra 4wd rear posi question
 

So i do have the G80 option, so im gonna try and see if its the fluid. Whats the easiest way to change it? do i have to remove the pumkin cover like on the older trucks?

Brad

Re: 2000 sierra 4wd rear posi question
 

yes. but remember just because you have posi doesn't mean your not going to get stuck. if you change the fuild please go to gm and get the fuild and special additave for the posi rear ends

Re: 2000 sierra 4wd rear posi question
 

Doesn't sound right for a failure at 87k. You have a locker rear axle....should have gotten the traction to both wheels equally, was the other wheel on dry pavement?

Re: 2000 sierra 4wd rear posi question
 

Well im not saying i wont get stuck, but like gray ghost asked, yes the other tire was on dry pavement, and was not moving at all, i was watching it while the other was just sitting there spinning....I would most likely get the service done at the dealer as i have never really done anything on rear ends before...

Re: 2000 sierra 4wd rear posi question
 

It's easy to change the fluid...pull the cover, use black RTV for a new seal... there will be one fill plug that gets removed and filled back up to that line...

Re: 2000 sierra 4wd rear posi question
 

I just thought about the fact that your G80 might be a limited slip. You can tell the difference...the locker makes a noise and a clunk when it locks up, limited slip is usually very quiet. If you had a limited slip there's probably nothing wrong with it....you were just stuck.

Re: 2000 sierra 4wd rear posi question
 

Hm weird, i also tried it in my driveway quick, which had snow on both rear tires, and still only one went, but it did switch sides in the beginning, so i guess it is still kinda workin, haha.

Brad

Re: 2000 sierra 4wd rear posi question
 

Sounds like a limited slip if it changed.

Re: 2000 sierra 4wd rear posi question
 

ok cool, so is there any other way i can tell if its a limited or a locker without takin off the diff cover?

Re: 2000 sierra 4wd rear posi question
 

call the delaer and have them run the vin number they should be able to tell you whats in there

Re: 2000 sierra 4wd rear posi question
 

Let us know what you find out.

Re: 2000 sierra 4wd rear posi question
 

Will do, thanks guys.