Lock up Switch

[speedyjdl]

As long as your transmission is built for it there are no negative side affects until you try to stop. The TC has to unlock to come to a complete stop without killing the motor. It would be like trying to stop a truck with a manual transmission with only hitting the brakes and not pushing the clutch in at all.

 

[cerberusiam]

The TC has to unlock to come to a complete stop without killing the motor. It would be like trying to stop a truck with a manual transmission with only hitting the brakes and not pushing the clutch in at all.

Yeah, and it makes REALLY bad noises when that happens, especially on a dyno. :-laf



Essentially there are no negatives to having the TC locked as much as possible. Full power is transfered to the wheels instead of loosing it thru the fluid coupling, no heat generation in the TC, and when the TC is locked you have full line pressure routed to the cooler to circulate fluid and cool it better.



Locked is good, the longer and more often the better.

 

[Gray 5.9]

What kind or size of resitor, ohms? should be used. I had a 94' with this setup and didn't need a resistor. I guess it has to do with the computer throwing trouble codes, or going into limp mode. BTW, It's been a long time since I've posted on the TDR

 

[Dave04]

So I have a 2004. 5 what do I have to do to hook up the switch.

 

[cerberusiam]

Tap pin #7 on the transmission control harness with a scotch lock or your choice of connector. Look on the trans side of the plug ad you will numbers marking the pins.



Run a 16 gauge wire into the cab to desired location on one side of a SPST switch.



Run the other side of the switch to a 1/2 watt 33 ohm resistor then to a chassis ground from the resistor.



This will ground the lockup solenoid and bypass the ECU doing it yet will keep the resistance within spec so the ECU does not see a problem.



This will work on everything all the way back to the 47RH units in 94's. The older trucks don't need the resistor but not sure at what point the computer may throw a MIL for solid ground in the circuit.

 

[Dave04]

OK I will give it a try.

 

[Linedog]

Has any one done this with the PAC brake, so when you put the brake on it automatically locks the transmission.

Joe