My buddy has a 12 valve with and automatic, and he just installed a switch to ground his torque coverter so he can lock it up when he wants. Myself on the other hand have tried this, and had no sucsess. I found the wiring diagram for my 00' 24 valve's 47RE, and installed a switched ground to the torque converter clutch solenoid. When i flip the switch the torque converter locks breifly then the tranny kicks down. After that it tries takin of in second gear and you have to manually shift it. After you unplug the ground goin to the tcc solenoid wire, and turn the truck off and on again it shifts fine. If anyone knows the solution to this question, please let me know. Any help would be greatly appreciated! Thanks.

 

You have to bypass the relay with a jumper wire. Someone jump in and give the link. Its on TST's website I think.

 

i just bought a BD kit to do just that, i will get it in this weekend. This is made for a exhaust brake but it has a manual position that i will use on long hills.