I have just purchased a 1997 12 valve. I love the truck and have just started having some issues with the 4 gear shift and lockup on the converter. I know there are many options for locking up the converter and also you can do the ground wire. My problem is I am lookig for a solution.

I have relplace the valve body with suncoasts 487 upgrade with all new sylenoids. I also put a mag pan on at the same time. This did resolve the issues with the sylenoid that was making it start in 2nd gear. However, the problem still remains for the 4th gear shift and lockup.

Initially the trans will shift ok. I do park in a garage, but I am in the mountain west, and temps are now starting in the morning close to freezing outside. When I hit the highway, after driving, it may have locked up, but then it will kick out. I have to really get on it to make it shift up, but then it may or may not go into lockup.

This seems to be temperature related. I can be up to full engine temp, water temp is fine, but trans will shift wierd. I have not put a trans gauge on yet, so I am not sure on the oil temp. I know it sounds wierd, but anything around 50 degrees or so AMBIENT air temp has been causeing the problem. It will work just fine, no issues at all in the afternoon and early evening.

I have read on the TPS and other possibilities, buit I am trying to figure out what to do. Rather than hooking up a ground I am considering buying a lockup controller like (TS, ATS, BD,) or something along those lines.

Can anybody give me any insight. This can be very frustrating. I know 4th gear and lockup are electronically controlled, but there has to be a solution. I have read also that if trans oil temp is 50 degress, or lower, it will inhibit 4th gear and lockup.

Thanks in advance for any help you can give.

 

improper or erratic tps signal can cause this, some guys install a potentiometer so the PCM continuously reads a set voltage and once up to governor pressure, which is supposed to correlate to vehicle speed; it locks up... some guys get away with installing a diode in the signal wire to the PCM it "cleans" up the signal if there were any kind of interference with it... when you say its temp related it can also be an electrical problem still... temperature changes resistances, which is what all thermisters (temps gauges) operate on... good to know about the starting out in 2nd problem was solved with a valve body tho... our truck has done that forever... if the parents ever get tired of it i know what route to take; thanks

 

Just an update. Sorry for the delay, but everything is working perfect. The problem ended up being the "crank posistion sensor"? I think. It was the one that reads off the factory dampner or counter balancer. The spacing was off. It was too close, so when the temps got colder, and with the force of it going round and round the tolerance became to close to get a reading for 4th gear. Kind of crazy, but everything works good. Truck is coming along very well and I love this thing.

 

Good to hear, Mind me asking what you set your cps at? Your problem describes my truck, and I've got to the point I just gave up.

 

i know exactly what you mean, i even put a governor pressure sensor in. sometimes when coming to a stop, the truck will almost die or it will die.did you install a new cps or did you just reset the old one. i also installed a toggle switch on the orange wire going to the pcm

 

cps .050