Junk yard rear differential interchange options.
 

My 72 c10 with rear coils requires a new rear end. What are my options for a complete swap from a junkyard? There are very few 67-72s to choose from locally, what other vehicles would be a good donor for my truck? I have searched the site and web for widths for GM vehicles, but the results are limited.

I am not worried about welding the perches or other items on the new differential. I'm just looking for the correct width.

What axles have you been able to use successfully?

Re: Junk yard rear differential interchange options.
 

If your going to swap the rear axle out anyway why not upgrade the thing?

Put the truck up on jack stands, pull off the wheels, run three lug nuts down per side until the drum or disc is sitting flush with the hub. Use washers or a large socket if need be so they sit tight.
Grab a paint stick and tape it to the "wheel mounting surface" . Then tape another stick to the other side. Grab a tape measure and run it across"extra set of hands help" attaching it to the paint stick and you have your measurement for your truck.
This works even if the axle has been shortened or messed with in some way at some point in the last 45 years.

Not knowing the entire history of your truck this is the best method I can recommend so you do not find yourself rubbing fenders or frame when you throw the wheels on.

Once you have your measurement it is a manner of finding a axle with the same measurement and ratio that suits your application and welding up the mounts.


If you managed to bend your axle then tube and would rather throw another in then fix it then yea the 10 bolt is good in most instances. If you want to go to disc brakes a 8.8 works if it fits your wms. 9" works and has a removable carrier that I like. Chrysler 8 3/4 also has a removable carrier are easier to find then the 9".


Do the paint stick thing and find your wms then you will be able to find a entire list of different axles to choose from.

Re: Junk yard rear differential interchange options.
 

You '72 12 bolt will have a WMS to WMS of 63.5". That is the same as the truck 12 bolts from '73-'82 and the truck 10 bolts from '79-'86 in the C series and '87-'91 in the R series trucks, Suburbans, etc.

I don't know what is wrong with the 12 bolt you currently have under your truck, but I would suggest rebuilding what you have. Sure you could find another differential to put under your truck, but who knows how long another used differential is going to last. And that is after you have welded on the trailing arm mounts and fabricated a panhard bar mount.

Re: Junk yard rear differential interchange options.
 

All great points. Thanks.

I am currently looking for a spare unit since I purchased another project and the PO mentioned it needed rear brakes. After disassembly, there was no brake parts so I thought I could get a complete rear end for the same price. Not for the long haul, but for the time I want to take for a test drive to see what shakes and rattles more or less.

Re: Junk yard rear differential interchange options.
 

^^^ This... 100%

Gary