I just purchased a car with a full manual valve body 4l80e & I noticed it was leaking pretty good & then started to slip 2nd gear hopefully it's low fluid but probably burned the clutches when I got under it I noticed they drilled a hole in the back of the case on top & ran 2 wires through it which I assume are for the converter lockup which isn't even working. My 1st question is why drill into the trans? 2nd why might the converter not be locking up? Previous owner said it worked 3 times then the switch quit working it's on a toggle switch but nothing happens when flipped up.

 

Regarding the converter not locking up, first ensure there is power to your toggle switch. If you do have power to the toggle switch, make sure that you have power going to the trans and it is not grounded out somewhere possibly blowing a fuse.

As for the hole that was drilled, I have to agree with Gearhead115's comment.

 

4L80E PCC is PWM, not on/off. If the 4L80 is supplied direct voltage to the TCC solenoid it will burn up in short order...looks like it took three times on yours.

 

Not true.

 

X2. My "PWM" TCC has been on/off for years.