I am investigating a gearing change for my 96 12v automatic (2500) which has a dana 70 (4.10). I have an opportunity to pickup a dana 80 that has the 3.54 ratio I would like, so I does anyone know if that will bolt in as a replacement rear end or are there other issues that I would need to address?

Is the 80 a srw? A lot of people make this upgrade. The 80 has disk brakes right?

You can swap them easily. The Dana 80 swap will require the driveline to be shortened 1 inch or just take the driveline from the donor rig. Then you will need the u-bolts and upper u-bolt plates from the D80 donor as the axle tube diameter is larger on the 80 and the u-bolts from the 80 are a bit wider and thus require the wider u-bolt plates that sit on top of the spring pack. Other than that it is a direct swap.I know because I did the swap on my 02.As far as the disc brake comment, only the 01.5 and 02 rigs came with disc brakes.

Thanks, for the quick replies. The donor rear end is SRW and since it is from a 96 2500 no disc brakes.

I think that would be a useful upgrade. Better if it had the rear discs but still worthwhile. I have the 4.10 ratio & it does nothing for me except cost me mpg. IMHO, 4.10 is only useful if you are going to run big wheels to cut the ratio back down. 3.54 is a good ratio.

3.54 is a good ratio but if your towing daily like CajFlynn the 3.73 is also a good mix...

3.54 is a good ratio but if your towing daily like CajFlynn the 3.73 is also a good mix...

Yeah, you kinda get the good of both with the 3.73.........not the best of both!!

You can swap them easily. The Dana 80 swap will require the driveline to be shortened 1 inch or just take the driveline from the donor rig. Then you will need the u-bolts and upper u-bolt plates from the D80 donor as the axle tube diameter is larger on the 80 and the u-bolts from the 80 are a bit wider and thus require the wider u-bolt plates that sit on top of the spring pack. Other than that it is a direct swap. I know because I did the swap on my 02. As far as the disc brake comment, only the 01.5 and 02 rigs came with disc brakes.

Actually i did this swap too, and iirc the u bolts go down over the springs so all you really need is the bottom plates that wrap around the axle housing, your old u bolts and top plate will work fine. Driveline does need to be shortened.

Actually i did this swap too, and iirc the u bolts go down over the springs so all you really need is the bottom plates that wrap around the axle housing, your old u bolts and top plate will work fine. Driveline does need to be shortened.

Thanks I forgot to mention the bottom saddle plate as well and the U-bolts will work now that I think about it but the upper plate is longer due to the larger diameter axle tube.

Thanks I forgot to mention the bottom saddle plate as well and the U-bolts will work now that I think about it but the upper plate is longer due to the larger diameter axle tube.

Thanks for all the info. I picked up the axle last weekend and just need to gather a couple parts and then find a few hours to swap in.

I have the d80 in the garage and getting ready to swap. Since I dont know when it was last serviced I plan to change the fluid before install. I cant seem to find a listing for the fluid capacity that is clear. Documentation indicates a differenent capacity for a D80 in a 4x4 vs a 4x2 application:Lube Capacity 4x2 6.8 pints ( 3.22 L ) 3.4 Quarts4x4 10.1 pints ( 4.79 L ) 5.05 QuartsAre the 4x2 and 4x4 axles actually have a different capacity, or is it a different "fill level" depending on the drive configuration?

I have the d80 in the garage and getting ready to swap. Since I dont know when it was last serviced I plan to change the fluid before install. I cant seem to find a listing for the fluid capacity that is clear. Documentation indicates a differenent capacity for a D80 in a 4x4 vs a 4x2 application: Lube Capacity 4x2 6.8 pints ( 3.22 L ) 3.4 Quarts 4x4 10.1 pints ( 4.79 L ) 5.05 Quarts Are the 4x2 and 4x4 axles actually have a different capacity, or is it a different "fill level" depending on the drive configuration?

I'd just buy 5 QTs and put 3 in and check it and go from there best way to be sure so u dont have to make extra trips to the store and what u don't use keep as extra or return. Also is this axle a Limited slip? if so you will need Limited slip additive Good luck

Thanks I forgot to mention the bottom saddle plate as well and the U-bolts will work now that I think about it but the upper plate is longer due to the larger diameter axle tube.

So this can be done for going from drums to disk at same time ? Thought I read somewhere there were issues with this ...

So this can be done for going from drums to disk at same time ? Thought I read somewhere there were issues with this ...

You start running into things with the brake valving and priority valve ect due to the drums and discs having different piston volumes. Brake lines might be different as well.

You start running into things with the brake valving and priority valve ect due to the drums and discs having different piston volumes. Brake lines might be different as well.

I was sketchy on this as well bit when i swapped a 02 D80 into my 98.5 i had no issues. Just bolted it in and deleted the proportioning valve and it worked pefect!