First it is a 4R100 trans and the engeneer at Banks told me it was every bit as good as a Alison! They informed me that it shifted better and if one replaced the torque converter and put on the trans comand on it, that it would last the life of the truck. I did both and I added a temp gague. Under load in overdrive it just reaches 200 degrees. I live in California and will pull the hills going up to Mt. Shasta in overdrive, no problem, I must say that I have put a B&M fined pan on the tranny - and that did drop the temp. The last GM truck I owned was about 1960, and it was a 1947 chevy. I still own a 1970 Toyota Hilux, which is almost totaly restored. It is a one ton truck and the last of the eyebrow turnlights pickup. I am going to put it up for sale real soon. By the way - my truck is a 4x4 daully.