The GM 8-1/2" 10 bolt rear axle first appeared in vans 1976, however it did not come into widespread use in GM trucks until 1979-1981 when it replaced the 8-7/8" truck axle. From 1982-1987, this 10 bolt axle was used by all the GM 1/2 ton truck models. From 1988 on, the 8-1/2" axle has continued to be used for 1/2 ton class vehicles, plus some 3/4 ton vans. When AAM acquired the GM axle manufacturing assets, the 8-1/2" was renamed the AAM 860 8.6" 10 bolt rear axle.
FYI I had an 88 k20 3/4 chevey pickup and it had the 14 bolt 6 lug 8.5" and was rated at 5200 I think..( GVW was 8600 I think) It was a long time ago...
And as I said its crazy my RPO zr2 has 2270 lt tires. Thats 9080 lbs at 50 psi.
And if the axles are indeed 3750lb thats 7500 lbs..
As someone said my axles are weakest link..
I still think if I beef the leafs I can have a hauler.... But need to dump V8 in there...lol
From yeaterdaystractors .com
I know most all axles will carry much more then the published load-capacity. I assume they won't last as long when overloaded, but I know many work fine.
I'd just like to see the specs.
My GM 10 bolt rear 8.5" has axle bearings that measure: Inside diameter=1.6180"; Outside diameter=2.5778"; Width=1.303"
My GM 14 bolf SF 9.5" rear has axle bearings that measure: Inside diameter=1.7080"; Width=1.320"; Outside diameter=3.0880"
That's a pretty substantial difference. The 10 bolt is rated 4,000 lbs. so it seems the 12 bolt must be 5000-6000 lbs.
Ill find the facts that the axle is rated 3750 and post...