I have a 1989 V6 2WD rear axle for sale. It is an 8" differential, and has if I remember correctly 3.42 gears. Anyway, since it is an 8" diff, that means you can find all sorts of other ratios and lockers for it if you want. This one is complete from drum to drum. It also includes an inspection/fill port on top to make adding fluid easier. I replaced the axle bearings and seals when I had it in my truck. You may want to replace the pinion seal as it appears to be leaking a bit. The axle is in Merced CA, 95340. You would need to pick it up, as I won't ship it. I'd like to get $125 for it.
Would you happen to have an auto trans kicking around for that truck or at the very least a torque converter?
