[valiant67]

A rear end from any F, J or M body will fit, but they were offered in both 7.25" and 8.25". Personally, I would never put another 7.25" axle under it, they are easy to break. I'd get an 8.25" which will bolt right in but requires the driveshaft be shortened a bit. Axle ratios will vary. Most V8 cars had a terrible 2.2 gear (especially 1980 and later) though cop 318-4 cars would have a 2.9 gear. Slant 6 cars usually had a 2.7 or 2.9 gear. There was also less common 2.4 and 3.2 gears. I'd never put a 2.2 or 2.4 gear behind a slant 6 if that's what you've got.

 

[TWX]

I think that valiant67 meant "F, J, or M" instead of "F, F, or M".

Basically any non-wagon featured on either if these pages should direct-bolt-in:
https://www.allpar.com/model/aspen.html
https://www.allpar.com/model/dodge-diplomat.html

Lots of choices from about '76 to about '89.

Apparently an early B-body ('66-'70) axle is pretty close too, but may require spring perch work to make fit. The advantage there is that it could be all-new parts if buying that way, but will probably be more expensive.

 

[valiant67]

There is no difference in dimensions in the wagon axles for these cars compared to the sedans. So any F/J/M will work (other than the wagon is more likely to have an 8.25" axle than a 7.25") axle.
And yes, F J or M (fixed it).

 

[dana44]

And to check which models/years this applies to, look at the cars section of this site, 1977-1989 is quite a few years to choose from other than just the Volare. I do agree with the upgrade from the 7.25 rear end. It is far cheaper for a person that knows how to fit drivelines to cut and shorten one than it is to lengthen one, or, for a few extra bucks, pick up the driveline (measure first to verify length) and pick it up to, then return your slightly longer one for a refund!

 

[TWX]

There is no difference in dimensions in the wagon axles for these cars compared to the sedans. So any F/J/M will work (other than the wagon is more likely to have an 8.25" axle than a 7.25") axle.
And yes, F J or M (fixed it).

Was this the first unibody wagon that didn't have a different axle than the sedan or coupe?

 

[valiant67]

I don't know for sure. The B body wagons had a wider axle compared to the rest. But I think the (early) A body wagon axle was the same as the rest. So the F/M was like the A body in that respect.

 

[Bearhawke]

I don't know for sure. The B body wagons had a wider axle compared to the rest. But I think the (early) A body wagon axle was the same as the rest. So the F/M was like the A body in that respect.

1971-78 B's apparently used a C body based rear end assembly under the wagons.

 

[valiant67]

1971-78 B's apparently used a C body based rear end assembly under the wagons.

C body width flange to flange with B body width perch locations if I recall correctly.

 

[Bearhawke]

C body width flange to flange with B body width perch locations if I recall correctly.

Which makes sense since the axle shafts are the same between the B and C within the same ring gear diameter families (8 1/4 or 9 1/4") although some of the early 1970's B's probably used 8 3/4" rear ends along with C bodies till 1973.

 

[CbodyMoparFan]

I have a rear out of an M Body Police package. Located in CT. 2.94 gears non-sg. Less backing plates.