Non gov lock posi Gm 8.6

[81cutlass]

Kinda a non G body related question but GM nonetheless.

GM changed the 10 bolt 8.5 to 8.625 (commonly called an 8.6) for 99+. They have 30 spline axles and are somewhat interchangeable backwards to the 8.5.

I am looking for a 30 spline posi unit but am looking around to see what factory GM options there are.

Did GM put any non gov-lock posi in 99+ gm pickups/SUV's? I can buy a eaton clutch style or whatever aftermarket one for $350+ but I also would like to do a gear change and I can find $100-$300 posi suburban/pickup rears all day long. Just want to find one thats a non gov lock to make it worth it.

I'd rather buy a whole surburban/truck posi rear axle and just pull the 4.10 gearset with carrier and all out and swap into my rear without worrying about setting up gears.

Thanks!

 

[Yav8]

Look for the cop cars that had the HD suspension. You can tell by the 5 on 5 bolt pattern on the rear axels. I did the same thing and used a cop non govlock for my 90 GMC with the 30 spline axels. Not sure what gear the came with but it worked for me on the cheap. $100 for the complete rear end assemble, pulled the posi and junked the rest.

 

[Bar50]

All of the non gov-loc posi units I have found were in Suburbans with tow package. Most are 3.42 or 3.73.

 

[81cutlass]

All of the non gov-loc posi units I have found were in Suburbans with tow package. Most are 3.42 or 3.73.

So 99-07 suburbans with tow package? Does it matter if 4wd or 2wd? Thats good news, at least it gives me a place to start looking. How many have you found, is it pretty consistent? Most of the yards around here aren't "You Pull" so I get a little afraid to tell the person to pull a G80 equipped rear out of a suburban with a tow package and then get a gov lock because they don't know the difference.

I just wish I could find a 4.10 gearset!

My problem with a B body is the 8.5/8.6 interchange and I would really like a 3.73/4.10 gearset. Most of the B body ones I see are 3.08 or less which means series 2 carrier and nogo for my high 3.xx gears. Maybe I am being too picky/cheap and just gotta go aftermarket.

 

[Bar50]

I am pretty sure that the 30 spline deal started much earlier than '99 like 90...my '90 Suburban has 30 spline axles and a clutch type posi.

But, there is something to be said about spending more money to go cheap than it costs to just do it.

There will not be any 4.10 8.5 or 8.6, or, I have never seen any 4.10 ratio sets.

 

[81cutlass]

That would make sense. It seems like there is somthing around 88 where they changed from 28 to 30.

I found this link which makes it sound like all I need to do to put an 8.5 carrier into the 8.6 case is some special bearings.
https://www.my4by.com/gm-10-bolt-8.5-inch-vs-8.6-inch.html