[powerstroke73]

Actually according to Ford's ratings the 4R100 is supposed to be good to 1000lb/ft of torque. Thats a big supposed to be, its actually about 600-700. The stock 02 7.3L for example puts out 525lb/ft of torque. A tuner on the tow setting easily puts it over 600lb/ft going through the trans, and they typically don't blow the trans out. Its when you get up to the 100hp+ race tunes that problems show up. These are adding around 150+lb/ft of torque which gives you around 675 total going through the trans. I agree though that its nowhere near good enough to handle 1000 like they say.

The 4R70W is also a very poor trans. I toasted one in my old 97 F150 with just 35s and 3.55 gears. I took them off and went back to 285s and did some light towing (after the rebuild) and the trans was going south again when I traded it. I'd only rank it about a single notch above the infamous A4LD.