I need to manually control the shifting of the transmission in my 1988 pickup due to computer issues. There is a plug with three wires going into the trans mission midway up the pan on the driver side, and another plug at the tail. Does anyone know the functions of the wires on these plugs and what voltages they need to operate?

 

You got me lost,"you have to control it manually due to computer issues"? An 88 should have a 700R4 which is not computer controlled. While not a trans expert I think the front plug is for the converter lock up and the rear is for speedo. All use 12 V I beleive.

 

OW is correct. a 1988 is non-electronic. All there is is the harness for the lock-up solenoid. I m not sure the speedo is electronic. I think it is a mechanical cable with a cog on it in an 1988.

If you want to manually shift you will have to work it like a 3 on the tree. Start in Manual 1 upshift to 2 and then to D.

 

I figured it out as the converter lockup control. I thought the trans was not computer controlled, but gaps in the years listings I could find left some doubt. I believe the rear connection is the speedo...no cable. Does anyone here know the pin out of the lockup connector? What I have done is put an older engine in place...carb/points...due to the original just being plain worn out and the fact that I had the other. With no computer controls connected to the motor, the lockup never actuates. I may have a long trip to take, and a manual control of converter lockup would save quite a bit of fuel.

Love the '98. Had a coupe that color back in the day. No FB login needed to see it.

http://www.facebook.com/photo.php?pi...&id=1187962640

 

Please help, I have an 88' c1500 transmission issue. when truck is running and I put it in drive the motor shuts off. reverse and neutral is fine. Any ideas????

 

Drop the pan. In place of the 4th gear switch, install a 52 lb, normally open, 2 connector pressure switch.

Wire it: Ignition power in to the converter solenoid, out to one side of the pressure switch. Other side of the pressure switch to ground AT THE VALE BODY.

Put the pan back on and you're good to go.

Allan

 

You mean that Drive just flat kills the engine?

Possible bad converter solenoid, shorted 4th gear switch and/or wiring to ground; OR maybe the reverse input clutch is welded.

If the latter is the case, she's gotta come down outta there.

Does the truck try to move forward in neutral?

Allan

 

thanks for the help. we'll see what happens.