Torque Converter Lockup??

[kcarsey]

I have a pretty random question about something related to my 1999 ranger 4.0 auto with the 5r55e. The other day I was out in the woods playing around and trying to climb a muddy hill in my ranger. My truck is 4.0 ohv with the 5r55e automatic 4:10 gears and 31x10.50 tires. Anyways, on steeper muddy climbs, I have noticed that 4 high in 1st gear is too high, 4 low down in 1st gear is too low, but 4 low in 2 seems perfect for general mudding, and climbing hills. Does not lug the engine down too much, and I always have enough power to spin the tires. After having a scanner connected to my truck, I noticed that when the shifter is in the 2 position, the transmission seems to actually be in 3rd gear which I thought was odd.

My question is: is there a way to prevent torque converter lockup when the gear selector is in 2nd gear? I find that if i get enough wheel speed in 2, even under WOT the torque converter will lock after a few seconds, then the motor will lug down, and then the torque converter will unlock, and repeat. Not only is this probably hard on the lock up clutch in the TC and causes excess heat, but it causes the engine to bog down and lose wheel speed.

Is there a way I could put a toggle switch on my dash and wire it in to prevent the torque converter from ever locking up when in a situation like this? I know that if I touch the brake which keeps the brake switch engaged then the TC will never lock up, but I would like to have a more seamless way to keep it unlocked without activating the brake switch.

Any ideas??

 

[adsm08]

Don't you have a tow/haul button?

And yes, manual second is third gear.

 

[kcarsey]

Don't you have a tow/haul button?

And yes, manual second is third gear.

I have the OD cancel button which just keeps it from shifting into 5th but still allows TC lockup.

 

[adsm08]

It should also modify TC lockup strategy.

 

[kcarsey]

It should also modify TC lockup strategy.

I was not aware that modified when/how the TC locks up. I will try turning OD off next time and see what happens. If it does not behave how I want, i'll dig into the diagrams and see if I can figure something else out.

Thanks!

 

[adsm08]

If that doesn't do what you want the purple and yellow wire at the trans is the TCC solenoid control.

The only caution I will give you on putting a toggle in line to shut the clutch down is that when the circuit code sets (and it will) you might put the trans into a limp mode that makes it act strangely.

Also, I can't find the page where it tells you which way the solenoid operates (does turning it on apply or release the clutch). If cutting the circuit with the switch doesn't do what you want you would need a 3-pin switch that will ground the circuit to keep it off.

 

[kcarsey]

If that doesn't do what you want the purple and yellow wire at the trans is the TCC solenoid control.

The only caution I will give you on putting a toggle in line to shut the clutch down is that when the circuit code sets (and it will) you might put the trans into a limp mode that makes it act strangely.

Also, I can't find the page where it tells you which way the solenoid operates (does turning it on apply or release the clutch). If cutting the circuit with the switch doesn't do what you want you would need a 3-pin switch that will ground the circuit to keep it off.

I was hoping there may be some way to tie in indirectly through the brake switch, or some other way. If manually disabling the solenoid would bring on a cel or put the trans into limp mode i'll probably just deal with it as is.

 

[adsm08]

If you want to make the computer think you are on the brakes all the time find the red/green wire, pin 32 at the PCM and rig your switch up to feed it 12V.

Just be conscious of leaving it on as it will leave your brake lights on all the time. That could probably be overcome by making the connection close to the computer and then placing a diode between your tap and the brake switch.