Engine/Transmission (1998.5 - 2002) TC unlock mystery switch

[MD500E]

I know there has been much talk in the past about the mystery switch. The question is, can I hurt the transmission by installing a switch that holds the tc un-locked. I have of heard warnings about transmission dammage by forcing the tc to stay locked up, but, I can't see any reason why it would hurt to keep it from locking up other than increased trans temp. Second question, when brakes are applied the tc unlocks, can i find the wire that triggers this and tap into it with a switch that will fool it? I drive 20 miles to work on back roads between 30-50MPH and the poor TC must lock and unlock over 60 to 70 times. I would love to be able to keep it off for this type of driving. Any ideas? Thanks!

 

[Jim Fulmer]

On TST's web site there use to be instructions for a lock switch, you can use the same instructions but instead of grounding the converter wire you would create a loop with two wires that run into the cab and to a switch or a floor dimmer switch like I did, I really like to be able to unlock the converter when I want to.



Jim

 

[danandamy]

unlock switch

I have an unlock switch on mine. Just find the wire that controls the lock up ( I think it's orange and black going into the top of the transmission) and cut it. Run both ends to an off/on toggle in the cab and your set. Switch the toggle on and you got normal operation switch it off and it can't ground/lock up.



dan

 

[Shooter]

It is a lot easier to get the or/blk wire at the pcm connector at the pcm.



JMHO

 

[MD500E]

If I wire in a switch to interupt the orange and black wire, i am guessing that i do not need to install the jumper wire in place of the relay in he electrical box? Thanks for the great info guys. I cant wait to get started!

 

[jboehm]

If it's that easy, then it's probably just as "easy" to set the high idle up... ... . (RIGHT! that's another thread!!!!<G>) Course, DC hasn't been easy to work with on that one either! Funny how they don't like us getting into the computer controls... ... even some of their tech's can't find out!

 

[Roger Ledbetter]

Trans code

I used a unlock / lock up switch before my last upgrade. It set off a code with the unlock just by opening the TCC connection. The solution was to add a 50 ohm 10 watt resistor to ground, makes the PCM think it is hooked up to the TC.

Worked great, I would use the unlock pulling hard up hills when the EGTs got too high and also when starting from a dead stop while pulling the 5th wheel, got to cruise speed then lock up, very nice that way.

Infact I am thinking of re installing it because I am having a hard time getting used to the commander locking up so soon when it is set up for the best braking.