So, the truck is down right now for engine problems (just swapped in a 6.9L for the 7.3L that lasted... a day!) but I guess I may as well figure out if its worth fixing the motor right now, or to wait till I have 10k to dump in the damn thing. So no rush! It's a 1994 F-350, IDI turbo diesel.

THE PROBLEM:
Basically, the lock up WORKS, it's just really WEAK. It is a turbo IDI truck, lifted on 35s, crew cab long bed 4x4 with 203k on it. Not sure if the trans is rebuilt or not. When you push the pedal down more than 50%, it slips. Shifts are firm as the trans shows a lockup code commanding max line pressure. Lockup is usually right at 30mph and it disengages during shifts as normal. (I now have a light indicating the lockup signal, as well as a switch that allows me to disable lockup completely, leave it to the computer to command it, or turn it on manually).

WHAT I WANT TO KNOW:
I would like to know what the possible problems/fix's are, and if running it with the lockup disabled is a problem. Since I CAN disable it and stop it from slipping, is that better than letting it slip? Or will it create too much heat, especially in overdrive? I do not have nor can I afford a temp gauge right now. So far as I know, the possible problems are a bad torque converter (obviously), or a leaking/cracked lockup apply solenoid. How would I fix a solenoid issue? I don't know where to find an updated valve body...

Thanks for any help!

 

You fix a bad solenoid by replacing it. Most likely it isn't the solenoid. It's probably a cracked torque converter clutch apply piston. The fix for that is a new torque converter.

 

Oh, the 'apply piston' that cracks is IN the torque converter?

I thought it was in the valve body, or at least whatever cracks and leaks is in there... The reason I was thinking that is because I read somewhere they fixed it in '95 (not sure where though lol)

If thats true then that makes this simple... I need a new torque converter... that'l have to wait 6 months lol. Will running the trans with lockup disabled hurt it? Maybe if I leave it out of overdrive (really don't want to with 4.10s...)

 

Keeping the lockup disabled won't hurt the trans, as long as it doesn't overheat. In cooler weather you should not have a problem keeping the trans cool.

 

How did you do the 3 way switch? Is it something you bought or built?