72 C20 rear axle
 

Having some rear brake work done on my truck. The 3/4 ton seals I ordered were too small. Takes a larger seal that should fit a 1 ton. It is a custom deluxe camper special with the heavy duty rear leaf spring option. It doesn't look large enough to be a 1 ton axle. 10 bolt cover so thought it was a dana 60. Any thoughts? My books don't mention anything about a larger option in this truck.

Re: 72 C20 rear axle
 

Since its leaf sprung, anything could be swapped in there but its probably a dana 60. Why don't you post a picture and we can go from there.

Re: 72 C20 rear axle
 

Even the Eaton has 10 bolts?. Is the cover round or diamond shaped?

Re: 72 C20 rear axle
 

Amazing the variations in just 1 year model options. Upon further research it turns out the since the truck was ordered with rear heavy duty leafs it has a 5500 lb Dana 60 rather than the standard 5200 lb axle that came in the 3/4 C20's. Hence the axle is a bigger diameter so bigger seal. Good news is that it should be a 4.10 ratio which I understand to be harder to find. Ordered a shop service manual that should be here today so better info in the future. Lots of conflicting info on the internet about these trucks. Getting an education for sure since I bought this thing.

Re: 72 C20 rear axle
 

Recommend look up member Hatzie, he has a bunch of downloadable manuals. Don’t have thread handy, but it’s very helpful.

Also handy are the spec sheets on the original sales brochures for the purpose of deciphering standard vs optional equipment. My 72 C20 Custom Camper with leafs was a D60/4.10 I believe 4.10 was standard for a C20 V8/automatic (regardless of rear end type) but would need to confirm.

Re: 72 C20 rear axle
 

My understanding is the D60's on the leaf rear trucks were all 4.10. As you know most of these were rear coil springs as the leaf was an option. The rear leafs without the heavy rear suspension option I believe were D60 5200 lb axles. The Heavy leaf spring option got the 5500lb axles unless a Cheyenne or short box. The Eaton axles were I think a 4.56 or lower and used on the coil spring trucks. Mind boggling the variations.

Re: 72 C20 rear axle
 

Here is some good information from the gm heritage center on power train combinations and gear ratios.

Re: 72 C20 rear axle
 

Here is a link, lots of great information here

https://www.gmheritagecenter.com/doc...olet-Truck.pdf