What to do about a useless limited slip rear end?

If you have a limited slip, Dodge specified how Dana built them with regards to the stacking and shimming of the clutch discs and steel plates for a softer feel and better tire wear. There is lots on the dodge forums about rebuilding the friction stacks with new parts and per the dana spec for an almost locker like feel. I believe it can also be a DIY job if you're handy.

One thing to try, riding the brake can help apply load to the diff to get the clutch plates to lock up more.