I have an ’81 300 SD and I’m pretty certain my rear end is in need of help, my car’s rear end that is. Mine is serviceable. This is a recent acquisition and I know very little of this rig’s history, but I think it was rode hard and put away wet more than once. But, the body is nice and the engine is sound enough, so…

I found an ’85 380 SE at the local pick ‘n pull and the rear axle looks just like mine and sounds a lot tighter when you rock the wheels back and forth plus the bearings sound better than mine. My question is, is this the same part exactly? Or is the ratio different and other things different as well? I remember the old network style wrecking yards had big reference books spelling that sort of thing out but I haven’t seen that lately. Anybody know?