I was wondering if a rear sure grip(limited slip)differential from a 98 Dodge 1500 4x4 would bolt into the rear axle housing of my 1991 w150, I believe both rear axles are 9 1/4" units, should also be able to re-use my 91 ring gear as well. Has anybody tried this and is it possible?

 

If you have the 9.25 then yes it is possible but not worth it. The 2nd gen factory trac-lok limited slip differentials are not very good and when they go bad will take out the axle. Also you would need to set the rear end up again even if you are using the same ring gear. If you want a limited slip buy an aftermarket and have it professionally installed or do a lot of reading to do it yourself.