loeworm

I'm trying to finish an rear diff swap into my 85. I have a 89, i think not too sure on the year, v6 diff. It has the four ribs and is 3 inches wider than the rear diff I pulled out. Are the u-bolts and mounts different? The newer diff is around an inch wider in diameter than the stock 85 rear axle.

peow130

*Sigh* have you considered the search function? this has been covered a million times before, and all have concluded that as long as the differential ratio is the same, and the spring perches are the same distance apart. They can be swapped.

loeworm

I don't have the 89's perchers, but thank you old great one.

4Crawler

iTrader: (3)

The '89 axle tube is 3" OD vs. 2.5" on the '85 axle. If you'll be using the stock u-bolt setup, you'll need the spring plates and possibly u-bolts off the '89 (depends if they are the narrow or wide spring perch version). If doing a u-bolt flip (u-bolts around the tube), you'll need 3" ID u-bolts and matching spring plates.

muddpigg

iTrader: (1)

sounds like the wider dif came from a late model truck or 4 rnr. I have a v6 dif in my '86 and the diameters are the same for the 8" 4cyl and 6cyl.

http://home.4x4wire.com/erik/diffs/ might help.

peow130

After 85, the rear axle housing got slightly wider to match the IFS track width, and a larger housing.
before 85, the rear axle is like a 2" diameter