My read Diff may be shot, so.....

[BBQ BOY]

There is a possibility that my rear differential may be shot. My Mechanic notice a very bad vibration. Put it on a lift and saw that the rear drive shaft was VERY LOOSE!! The back bolt has managed to work its way almost out from the flange. You could take the drive shaft in your hand and freely turn it 1/4 of the way before it caught. There is no telling how long it has been that way. Anyway I am wanting to put an Aussie locker on and if I do will that fix my diff. issue. Excuse my ignorance because eI do not about this stuff. If the Diff. is shot then what? Is an Aussie locker the same as a diff?

 

[high country cruiser]

Not necessarily.

The locker is just a part of the rear end .This would re-place your side gears which makes your axles turn at different speeds while going around a corner. It sounds like the pinion nut came loose which does not mean your gears are bad. You must remove the inspection cover to actually verify the inside.Good luck..... Turning the drive shaft from side to side is no indication of wear there always loose to some degree. Up and down movement is not good.........

 

[BBQ BOY]

If it needs to be replaced then what are my options? Cost?

 

[Cruiserdrew]

Usually if the flange nut is loose, it means the pinion bearing has worn enough to loose preload. the shims inside spin and wear more on the pinion shaft. this is pretty normal stuff at high miles.

You need to pull the diff and take it to a differential shop for a rebuild. Expect a $3-$400 repair bill. A new bearing kit is $150 or so and the labor to set it up is the rest. This is no big deal and normal. If you have them pull the differential, then double the estimate I gave.

As a stop gap, you can snug the bolt back down, but this just accellerates the wear on the pinion bearing which will loosen up even more and fail for sure. I can buy you a few months, though.

You also can swap the front and the rear differential. Typically the front gets very little wear, and so you can get good service from it in the rear. Then your worn diff can go up front, but again, you're on borrowed time.

An Aussie locker would be foolish at this point, at least until the diff is fixed.