The Stovebolt Site Forums The Shop Area Driveline HO72 Interchangability

I've got two HO72s. One is in my '56 3600 and is stock. The other is out of a 71 van and is stock. The specs are below:

1956-open differential, 4.57 gears
1971-detroit, 4.10 gears

My question is what is the best way for me to make a 4.10 open differential third member with these parts? I see it a few different ways but am not sure about the compatibility of some parts. For instance will the spline count of the shafts be the same? I want to keep my 1956 housing, shafts, and outers since I just added all new brake components and bearings.

-Pull the 4.10 gears out of the '71 axle and swap them into the 1956 open carrier and third member.
-Put the '71 third member into '56 housing and pull the Detroit/replace with open carrier.

I am not incredibly familiar with these axles. How difficult is it to set the bearing preload and gear backlash on these axles if I pull them apart?

I guess the easiest thing to do would be to swap the entire '71 third member in with Detroit and all (assuming the shafts are the same spline count). If I hate the Detroit I can then start creating a Frankenstein's monster with the two axles.

Thanks for any and all advise.

Take a look at this tech tip and I think it'll answer some of your questions.

http://www.stovebolt.com/techtips/axles/1%20Ton%20Upgrade/

Thanks. That did answer my question about the interchangeability of the parts (axle spline count being the same).

Another questions: Is a Detroit locker in these trucks going to be a bad idea? It is a 2wd 3600 which will see no offroad time no I know a locker is not needed. But to save me from swapping over gear sets and setting up the third members can I run the Detroit locker in the chevy with no ill effects. How terrible do ya'll think it will be on the streets?

Thanks.

I'm not an expert but I think the Detroit locker will allow you to turn on hard surfaces without skidding the tires. I have one in my '57 one ton and I can't tell the difference.