The transmissions are known to last the life of the car if given decent care. What you want to do with them is not decent care.

They are not built in the quantities of the domestic companies so after market devices to make them work better are not existent either.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.