Dana 80 Swap or not
 

I've been wanting to swap the gears from my 1992 dually from 4.10 to 3.55 for better mpgs and such. After adding up the parts it looks like it will be $700-800 for parts and labor. Well it happen to be that I found a dually Dana 80 from a 1996 for $400 complete drum to drum and it already has 3.54 gears. I'm curious how much of a upgrade is the 80 over the 70 and would it end up costing about the same? After doing a bunch of searching I've compiled the things that I'd need to do.

From Searching
- parking brake cables from 1996 which should attach the stock bracket
- new u-bolts and some modifications because the gen 2's have 3" wide springs as opposed to the gen 1 which have 2.5" and the dana 80 has bigger tubes
- 1.5-2" drive shaft shortening

Things I'm unsure about
- will I need new wheels or can I just reuse my stock ones?
- will the stock hydraulic line bolt to the axle line?
- will the speed sensor on the axle work with my wiring?

I say go with the 80, IMO the 70s are junk.

You could probly make the D70 Park brake cables work with the 80. One cable on the D80 is longer. I always upgrade to 5/8s bolt when doing an axle swap. It would be best if you could get the bottom spring plates from the 80 as well. The brake line will screw in, There is no speed sensor on either axle, they have what is called a tone ring for the ABS operation, but If you have working ABS it can be made to work.

You will also have to fab some shock mounts also.