I have a 1997 jimmy 4 door 4wd sle 40l60e trans, it drives fine for about 5 minutes, shifts normally, then i lose first gear. It wont shift down to 1st, i may or may not have overdrive, cant tell. I have replaced shift solenoids a and b, changed the trans filter and fluid. Does anybody have any ideas as to what would cause this? Also i dont think i have a bad starter ignition thingy as my key does not stick whatsoever but i do have CEL code P0785 shift timing solenoid

 

This is where you need to look. It won’t be the loss of power because that will set several codes. The key switch itself is not the part that fails it is a switch that is controlled by a rod that is activated by the key switch. On the column under the dash. Good luck and let us know what you find.

 

So i need to replace a switch under the dash or is it inside the trans? Would you have a picture of its location

when i replaces a and b shift solenoids i noticed the valve for the a (1-2) solenoid was actually sticking out of the valve body, i had to fight it with the solenoid to get it far enough in to put the clip on. Is that normal?

 

You need to replace the 3-2 coast down solenoid and check for a broken spring. I was saying it’s not going to be anything with the ignition switch. If it was related to that you would have several more trouble codes. Yes, one of the shift solenoids will be under spring pressure. Good luck.