Purchased the 2005 truck in 2004 adding the blower after 1st oil change and the daily beatings began.
140k miles now I'm surprised as bad as the G80 reputation is in an 8.5/8.6 diff its still together @140k+ miles. Add to that a decade of hunting and navigating 5100 acres of steep and rutted N. GA mountain roads.

As I research I find some occasionally find they have the 8.5 diff when the VIN parts search indicates otherwise and get the wrong bearings delivered. Some even claim if its drum brakes its an 8.5. Drums came back to the 2005 1500. I have seen pictures showing rear cover differences with the 8.5 having supposedly.
Is there any real chance I would have an 8.5 differential?
Thanks

 

It's hard to say for sure, I rebuild a diff in a 2003 s10 zr2 that has the smaller 8.5 bearings and then a 2001 zr2 blazer I did a regear on had the larger 8.6 bearings.

99% of aftermarket carriers are built for the 8.6 bearings. I have found it best to just have both sets of bearings on hand when tearing down late 90's to early 2000's 8.5 10 bolts, as I typically cannot wait on parts delays. it seems like they could go either way around that time.

If you can wait, id highly suggest tearing it apart, measuring what bearing size the housing takes, then ordering bearings accordingly.

 

The GMT800 should be 8.625. Not the earlier 8.5

 

Thank You Both.

So it seems having both bearing sets on hand is the safest bet. Will do.
Do you re-use the Ring Gear and Bearing Cap bolts? They don't seem to be TTY fasteners. I was looking at the Eaton install kit but they only mention the 8.5 in the p/n Eaton K-GM8.5-08R. Looks like a nice kit but don't want to get involved with returns, RMA's or arguments with them. Eaton Master Install Kit .

On bearings. I recently retired from an industrial maintenance purchase order & stores manager for two large manufacturing facilities, before this I was a maintenance tech since 1983..Many of our machines contain hundreds of bearings and are from several different countries.We learned to be wary of counterfeit bearings. The only way to be sure now days is to weigh them against spec weight. And a trustworthy vendor. We have seen missing *****, funky cage materials, and poor fitment and endurance. Ugly.

 

Ring gear bolts should be replaced. The cap bolts are reusable.

 

Are you going to do a crush sleeve eliminator?

 

My experience with the G80 is it holds up pretty well if you are going in a straight line. Drifting corners or doing donuts seems to be what takes them out.

 

Thanks,

Never heard of it. If I do the swap, the pinion will not be tampered with.

The more I look into it the more I lean towards not swapping. I have 140k miles on it and it performs great. I don't do low tire pressure launches, donuts, or drifting. Strictly pavement pounder now.

I admit until recently I never studied the inner workings of the G80 and lately I see folks arguing there are no clutches in the G80. HERE is evidence otherwise.

Another thing slowing my desire to do the swap is in 2021 I put the helical Wavetrac in my boosted 2013 Charger and very please with how it performs and has held up to the daily beatings. I call it a smart differential because it pretty much knows what to do in any situation. So having enjoyed the move to a helical diff the TrueTrac interested me.
But found they are two different applications of helical diffs.One difference is the Wavetrac will apply power to the wheel on the ground if one is in the air. The Truetrac will need the driver to apply brake. I was disappointed to find Wavetrac only makes one for a 12 bolt.

So thanks all of your replies. The project is on hold now.

The Charger 1 The Charger 2

 

My understanding is that the G80 is an automatic "locker," in the sense that once engaged or locked, the axles spin 1:1. The mechanism uses those clutches, so I think that's what confuses folks (clutches = slippage, right?). I admit I don't remember how the clutches work, however.

Compared to a LSD, where one axle may spin at a different rate than the other. Basically, the axles "slips" relative to the other. I don't believe that's the case on the G80.

Probably doesn't help that GM has used the same RPO code for other vehicles, that do in fact have true LSDs, like the F-bodies..."Posi" further muddies the waters even more, lol.

 

Also, the G80 will typically give you signs when/if it is heading south. I haven't had one working great one minute and **** the bed the next. they will go down hill and warn you before they grenade. If you ignore the signs it will eventually leave you stranded.