12 Bolt rear end?

[Dads64]

Looking for help so I order the right parts for my 12 Bolt.

It came out of my 64 C10 Short Bed Step Side but I am not sure it is original. Any tips for knowing for sure what I have would be great.

Here is the only pictures I have right now.

Thanks,
Jay

[Shooters_7]

what do you want to do? Jegs can help with ordering parts. Moser makes 5 lug axles #A30-65GMT5 to replace the old six lug. They run 260 for a set. Other than this choose a gear ratio, master rebuild kit and a carrier (I did an Eaton posi).

[Dads64]

I want to keep the six lug if possible but otherwise I want to rebuild it, new gear set and make it posi. So do I basicly just order all that stuff for a 12 bolt and it will fit?

Jay

[Shooters_7]

I just made sure mine was a 30 spline axle. I don't know what they were in 64 but I know its on this forum if you search. I'm sure someone else will chime in and verify what the exact spline count was back then. The axle may have been rebuilt somwhere along the way so I'd pull an axle out and see just to be safe.

[sigshooter]

It looks like the rear end a 64 would have ( different track bar on 65 and 66) 64 had a different spline ( 17 I think ) than the 30 spline 65 and newer. You can use 65-69 axles if you get the posi kit

[Captainfab]

Yes that is either a '63 or '64 12 bolt. The '63 had pressed on backing plates. The '64 backing plates are bolted to a flange that is welded onto the axle tube. Either way, unless it has been upgraded, that will have the 17 spline axles and side spider gears. You will have to change the axles to the 30 spline units used from '65 to early '70, to go along with your new posi unit. Basically most all parts interchange on the truck 12 bolt differentials, which were used from '63-'82.

[Dads64]

Well, I made out to the shop today and sure enough it is 17 spline. Guess I will need a full rebuild kit, posi, gears AND axles. So I should able to just order for a 12 bolt and be good right? Even LMC sells it all as 30 spline from I have found LOL

Thanks guys,
Jay

[Captainfab]

Yes....

Originally Posted by Captainfab

Yes that is either a '63 or '64 12 bolt. The '63 had pressed on backing plates. The '64 backing plates are bolted to a flange that is welded onto the axle tube. Either way, unless it has been upgraded, that will have the 17 spline axles and side spider gears. You will have to change the axles to the 30 spline units used from '65 to early '70, to go along with your new posi unit. Basically most all parts interchange on the truck 12 bolt differentials, which were used from '63-'82.

Originally Posted by Dads64

Well, I made out to the shop today and sure enough it is 17 spline. Guess I will need a full rebuild kit, posi, gears AND axles. So I should able to just order for a 12 bolt and be good right? Even LMC sells it all as 30 spline from I have found LOL

Thanks guys,
Jay

[Dads64]

Thanks again for the help. First go around at this so it is slow and steady with a lot of dumb questions LOL.

Jay