You *might* get away with dropping the pan and changing the fluid/filter and see what you get. The filter may be clogged causing the trans. to be starved for fluid. Compared to the amount a rebuild is gonna cost it might be worth a try. Be warned that it may also just be burning money as it may not help. Your call there.

I personally would try it, but I am my own labor so I'm just out the cost of the filter and a few quarts of fluid if it doesn't work. A shop on the other hand....

If it does need a rebuild I would contact Dave at triple edge performance and see what price he can give you on one. Granted you'll have shipping costs, but his are known to be worth it. Then you just have to pay a shop to swap it in.