As some of you guys know, I was looking for a 8.25 diff for my 79 D100 pick up. Called like fifty salvage yards here in the North East but no luck. Finally I called my buddy that I buy parts for my Jeep Wrangler and he was able to get me a 1974-76 Ram Changer Sub 9.25 rear end, they come with the smaller axle 5x4.5 bolt pattern which matches my lug nut pattern. When I put my old 8.25 next to the 9.25 everything matches up perfectly. The housing is almost the same length, been only about a quarter inch longer. The only thing is that it has the 3.21 gear ratio, I wanted 3.55. But, I will try this ratio and see how it performs with my 727 transmission and by sup-up 318ci.

Just wanted to point this out in case anyone having a D100 is in need of a diff and can't find the 8.25.

 

That is a GREAT upgrade for an axle. Thanks for the info too. We don't always get this kind of feed back with people do swaps.

The 3.21 gears will give you better gas mileage (if possible) and you'll have a higher top end speed, not much more though. You may notice a little change in the "get up and go" but probably not since the gear change isn't that great.

 

OK, so I installed the 9.25. Installation went smooth, except for getting the diff from my sawhorses to the leave springs by my self. I text drove the new 3.21 gears and to my surprised, it is very responsive off the line and I gained some top end. I am very happy with this Differential.

 

THat is great to hear. Do you know if the axle has a limited slip carrier in it? If you pick up the back end, the tires will either spin in the same direction or opposite. Same direction means you have some sort of locking device in there, opposite means the carrier is open.

 

Good job. Thanks for the update, I was wondering how you made out. Waiting for my new gear to come in for my 9.25.

 

This 9.25, is an open carrier diff. On a side note, every shop I went to, made this job into a project and some would not even touch it. Well I am glad, because I was a little scare st first since I never tackle anything this big but I really enjoyed the learning experience.