Posi (G80) but only right tire spins...Is it broke?

rah7777777 · February 21, 2012

Evening everyone!

I bought my truck a few years ago... 02 Silverado extended cab 1500. 5.3l, 2wd

I've always had an issue in wet weather with just the right rear spinning out.

Not hitting the throttle hard, just "getting into traffic". Sometimes the wheels spin is almost dangerous.

The right tire just winds up while the left just rolls along, un-powered.Tires have about 5k on them.

So I start looking into an aftermarket rear end setup after this mornings close call with my daughter in the truck.

(Again, not hot rodding the truck)

I look up the RPO codes and it shows I have G80 (Posi-rear end).

I've never heard it locking or unlocking while driving or turning, do these go out and still allow the vehicle to drive with out making any noises from the diff?

For grins, I tried a power punch in a dry lot and a wet lot. Had a friend watch the left tire. In neither condition did the left spin.

I rarely drive "fast" or "hard". It gets bad enough mileage with normal driving :-)

Any advice is appreciated. I serviced the rear diff about 5k ago. I don't recall seeing anything broken inside. Fluid wasnt too bad.

Any input is appreciated!

Thanks!

-Robert

Knowklew · February 21, 2012

10 year old rear diff.....the clutch packs in the G80 locker are probably shot.

Consider upgrading to an Eaton or something along those lines

rah7777777 · February 21, 2012

Thanks! those clutches might just be out.

Its just odd, it doesnt make any noises at all.

I've spent hours researching different rear ends and man.... that stuff is confusing.

Some say the Eaton G80 is good, some say it sucks... then there is tru-track and the detroit....... ahhh :-)

And I can't really tell if the stock chevy G80 is an actual eaton or just chevys version.

I drive my truck about 3,000 miles a year now. Its an 02 with 108k on the clock.

rah7777777 · February 21, 2012

I should also add, that I'm not a heavy foot driver. I don't race, the truck is all stock with the exception of a different exhaust setup

(Done by previous owner, personally its louder then I would like, but sounds like every other chevy V8 truck with exhaust on the road, haha)

I just don't want that 1 wheel spin to get my butt ran over. The parking lot of my daughters school is the hardest to pull out of and when it rains, I make the wife take her as the truck has caused a few "sticky" situations so far.

Now I see why my buddy loves his 03 Silverado SS (AWD) so much :-)

Thank You all!

-Robert

chakis24 · February 21, 2012

here's a vid how it works...plenty that coulve worn out (and theres really not much that locks it up):

also the locker will only engage if one tire is spinning >100 rpm's faster than the other AND youre not exceeding 20 mph

LURCH HD · February 21, 2012

Here's a thought, you bought it used maybe the first owner had it changed out to an open diff. My 02 had 291K on it and the G 80 still worked great.

Stevens03 · February 21, 2012

Also food for thought. If the previous owner put the wrong fluid it, it might not work. Check your owners manual for the correct fluid and do a swap. When you have the cover open, you should be able to confirm whether you have the locker or not and do an inspection. If everything looks good, put the correct fluid in and see if it works.

rah7777777 · February 22, 2012

The previous owner was my old boss. He doesn't think it was swapped out. BUT this is the same guy who had it for 95,000 miles and 7 years and thought it had a 4.8 liter engine ( turns out its a 5.3 )

I'm trying my hardest to remember the rear end internals from the last time I did the gasket. I used to be a tech for a European company and I'll I'm picturing are E-class gears haha!

I'll do it again and see. Thanks

Morgan1986 · February 22, 2012

He had it for 7 years . Does he drive on it hard . You would not know. Does his kids borrow it and drive the poop out of it. You dont know. This could of been going on for 7 years . If he did not know the engine type that most likely means the maintenance for 7 years was a crap shoot and even if he took it in for maintenance he should of know the engine type with the bill.

rah7777777 · February 22, 2012

I worked with him long enough to know how the truck was treated. It would sit every other week ( on call, so he had a work truck the others )

He was very anal about getting the oil changed and air filters. But... That's all as far as maintenance.

He never flushed the coolant, trans, power steering, diff, brakes. He did all highway so it had the original brakes on it.

Never had a tune up.

When I bought it I did EVERYTHING to it. Rebuilt the whole front end, FULL tune up. Flushed all fluids and changed all filters.

(Side note: I was very impressed that the trans fluid looked as good as it did for almost 100k on the clock. )

I converted to full synthetic on everything ( Engine, trans, diff ) pretty sure power steering too and I'm assuming brake fluid in general is a synthetic.

But he didn't drive very hard. (No kids either, haha.)

Couple years before I even thought about buying it, I borrowed it to get some parts for my car that was broke down and he made sure I wasn't going to beat on her haha.

But he did go hunting sometimes.. No telling what he did in the backwoods!!

herm0016 · February 22, 2012

are you sure you put the correct fluid in the diff? some syn fluid is not compatible with the g80, at least that is my understanding.

also, it is not a "posi" it is an automatic locking diff. very different in operation and use.

txab · February 23, 2012

are you sure you put the correct fluid in the diff? some syn fluid is not compatible with the g80, at least that is my understanding.

also, it is not a "posi" it is an automatic locking diff. very different in operation and use.

+1

No limited slip additives in a G80. Synthetics are fine