Rearend Chevy Corporate ?

[CJ5 Convert]

Hey all, I jeep seeing mentions of Chevy 10 and 12 bolts. As well as Corporate 10 and 12 bolt. Is there any difference or are they the same. Thanks -Jason

[Blazer1970]

Same thing

[danielwetpaint]

Chevrolet is "owned" by General Motors. So is Buick, Oldsmobile and Pontiac (known as B,O,P). There is a difference in the BOP 10 and 12 bolts as opposed to the Chevy 10 and 12 bolts. The BOPs are smaller internally and therefore weaker than the Chevies. They look similar to each other,,if you are looking for a rear end to go in front of Horsepower avoid them. Most are identified by "C" shaped notches cut into the sides of the rear end cover.There are several
Chevy 10 bolts available,the ones we mainly use have a rear facing access cover and load the gears and diff' through that opening.The Chevy experts tell us that the rear ends are aslo identified by the bolts that hold the ring gear to the differential,not the number of bolts that hold on the cover.But we still bend over and count the cover bolts,,lol. The chevy 10 bolt rear ends are identified by the ring gear diameter.First was the 8.2(1962-1972) , then 8.5(1973-1988), then later 7.5 (late 70's up to current). The 8.5 is the strongest,it came in car and trucks.Some say they're as strong as the 12 bolts.I've never broken one yet. The 12 bolts came in two versions,,car rear ends (Chevelles Impala's,etc) and Truck rear ends. Several parts don't interchange between them,including the cover. My memory is bad, I'm sure I forgot a few points,or made minimal errors in the timelines,but someone else will chime in.

[danielwetpaint]

I typed the above response and forgot to log in. When I had finished logging in,, it double posted,so I edited the double post out here.Feel free to remove this.

[CJ5 Convert]

Thanks all

[LONGHAIR]

If we are talking strictly "truck" axles, there is some confusion in terminology.

The older "removable 3rd member" HO/52 and HO/72 axles are sometimes refered to as 10 bolt or corporate 10 bolt too.
It is true that the factory discription of "bolts" is for the ring gear, but the cover happens to have the same count. That is probably why the HO/52 get called 10 bolt too.

Here is a quick discription of the most commonly seen diffs.
This is not all that there are, it is hardly an exhaustive discription, but in general a decent guide.

[Blazer1970]

Originally Posted by LONGHAIR

If It is true that the factory discription of "bolts" is for the ring gear, ..........

This is not true at all. GM never used this terminology in any way. GM identifies their axles by ring gear diameter. A 14 bolt axle only has 12 ring gear bolts.

[LONGHAIR]

GM identifies their axles by ring gear diameter.

Kinda makes you wonder why "we", as hobbyists, don't do that too? It certainly would take all of the car vs. truck thing out of the equation too.

It's similar to the "head" thing with Harleys. They didn't originate those terms (Panhead, Shovelhead, etc) either, but they have adopted them....and in Harley's case they even Copyrighted those words.

[Blazer1970]

Originally Posted by LONGHAIR

Kinda makes you wonder why "we", as hobbyists, don't do that too? It certainly would take all of the car vs. truck thing out of the equation too.

That would help, but there are still a bunch of different axles with a 8 1/2" ring gear diameter. There just isn't a good way to identify these axles at a glance unless you know exactly what you are looking for (especially if they are not attached to the original vehicle they came with).