Dave

Both the C-4 and C-6 can be made to last without major parts replacement. It depends on how you use it and how much power you're pushing through it. Even the heavy duty CJ C-6 like mine will wear parts under drag racing conditions after so many runs. Using the right fluid and keeping that fluid cool and clean definitely helps it live longer. I agree that type F fluid should be used although it's been stated that other fluids would be ok in my trans. My new engine makes approximately 680 hp and close to that in torque but the car is light at approx 2750 with me and fuel. However I'll have it on a brake leaving at 4500 rpm and that could be very hard on a trans. That's why I run the fluid through the radiator cooler and then through an air to air cooler before the fluid goes back to the trans. Thanks for commenting. George

67 428 Mustang Fastback Super Pro Drag Car
92 F150 P/U Trk
2002 BMW 3.0i Z3 Roadster
90 Acura Integra