Tranny cooler.
 

My Jimmy has a rebuilt 700R4. It was rebuilt about 8 months before I bought. No wanting another tranny failure while I own it, I installed an external cooler.

http://thumb13.webshots.net/t/63/663...3IZMuyh_th.jpg

Installation was easy. I also installed the lines reversed because GM changed the hose connections. After verifying the return line, I redid the lines for maximum cooling.