I pulled a G80 Diff out of a 88 S15 Jimmy 4X4 at my local U-Pull It junk yard for $60 cash. I plan on installing it in my 89 S15 Jimmy 2wd.
Before anyone comments on what a POS the G80 is I have read all of the comments and reviews I could find and for me I still wanted it for what it is designed for. "Low Speed Traction Device" and nothing else. All it needs to do is get me unstuck one time and it has paid for itself.
My only concern right now is the spline count of my existing axles vs the spline count of the G80 Diff. I did not bother counting the spline count n the junk yard as I do not know what my spline count is in my 89. I hoping that there was not a change between the 88 & 89 S15 Jimmy as far as the axle spline count goes.
Did u grab the carrier shims from the g80 rear? U might luck out and be able to use your current open carrier shims but not likely. Just make sure it's the same series carrier too. '88 is when they switched to the 28 spline axles but some still got the 26 spline. Count the splines on the carrier to make sure.
I did get the shims from the G80 and I know I might have an issues with the axle shaft spline count. Hopefully, I will not have an issue with the series. All will become clear when I pull my existing diff. I plan on doing the swap this weekend.
My original diff. is a 3:08 gear which is a series 2 case. I like the 3:08 gear ratio so I ordered a Motive 3:08 thin Ring & Pinion gear made for a series 3 case. I also ordered the Motive installation kit. I will modify the original pinion bearings to use as fit test bearings for setting the pinion depth. I have watched plenty of videos on Ring & Pinion set up. I should be able to install the G80 Gov Loc. Diff next weekend as all the prep work will done this weekend. I was unawares of the differences between the Series 2 or 3 case and the limits of each. But I found out that the 3:08 gear ratio has a thicker pinion and therefore the mounting flange for the ring gear is farther away from the pinion gear. So much for a plug and play installation. I thought all I would need to do is transfer my ring gear & adjust the backlash. This is not the first project I dove into that is more involved than I though it would be. I am very mechanical and I have all the tools I would need to accomplish the installation.