GMC GM drop out thrid member REAR END ID question
 

Ok the drop out is a 1964 date code on the ring gear
AXLE spline is coarse
ring and pinion ratio trying to remember (8 on the pinion 36 on the ring ) 4.50 ratio??? maybe a few teeth off

Anyway it have a 10" ring gear + or - a 1/4" ish

has a bolt in pinion from the front like FORD 9" (5 bolts)

Ring gear bolts are on the inner diameter of the ring gear NOT in the traditional late model back side of the ring gear behind the ring gear teeth (IE 12 bolt chevy 10, bolt 8.5 etc. )

Does have the fifth bearing like a Ford 9" also BUT bigger.

Does this sound like a c30 c40 c50 c60 truck rear?


I have casting numbers i can get too if that helps. Jim


Thanks everyone

Re: GMC GM drop out thrid member REAR END ID question
 

I know a guy who used one of these in his rock crawler. I don't know much about them other than they did come in 3/4 ton pickups and up. Correct they are factory 4.56 gears, and from what I recall he had a hell of a time locating pinion bearings for it, or they were extremely expensive, I forgot. But that is a BAD A$$ rear end my friend. Wouldn't necessarily put it in anything 2wd but definitely a 4wd beast. I'm sure there are plenty of people on here that can tell you more.

Re: GMC GM drop out thrid member REAR END ID question
 

Yha they are MONSTER axles even though they are coarse.

SEEMS to be built like a TANK. Jim

This guy has it at his house and needs to unload the ring gear does have some slight chipped teeth but it is a locker.

So if you know of anyone wanting this let me know I will forward the phone number.

I will try to get pictures. Jim

Re: GMC GM drop out thrid member REAR END ID question
 

I don't really know of anyone needing one at the moment. I'd post something up in the 4x4 section or could be a good craigslist item. Forgot about the locker thats another plus to these axles

Re: GMC GM drop out thrid member REAR END ID question
 

Yah I just want to get as much info on it as possible so IF I have to ship someone does not say it is not what was listed correctly...lol. YOU know how that goes. Jim

Re: GMC GM drop out thrid member REAR END ID question
 

What you are describing would be the Eaton HO52 or the HO72 rear differential. Yes they are tough as h**l and parts are hard to find and/or expensive.

Re: GMC GM drop out thrid member REAR END ID question
 

How can I tell if it is a locker or not? any place to look with out tearing open the carrier? Jim

Re: GMC GM drop out thrid member REAR END ID question
 

With the trans in neutral, jack up one side and try and turn the wheel. If you can turn it , it is an open diff. If you can't turn it, it has a detroit locker.

Re: GMC GM drop out thrid member REAR END ID question
 

LOL...You're a funny guy... I only have the chunk...No truck No rear housing... If I am looking at the casrrier How do I tell?

All parts are incased in the carrier unit, spiders can not be seen etc.

Are there clutches of number or can some one post a picture of a locker unit out of the housing with the tell tale signs? :0 Thanks much. Jim