Engine/Transmission (1994 - 1998) Lock-up first then unlocked

[NKenny]

The truck is a '94 4x4 with an unmodded engine and a seemingly stock (or stock rebuild) auto. It has 230k miles.



After driving occasionally for the past week, I have noticed that the transmission seems to dump into the next gear in Lock-up, than unlock rather than upshift unlocked and then lock-up. While slowing to a stop, it does feel like it is trying to drive through the brakes until it gets below 20mph (I have reached for my clutch on numerous occasions :-laf) My initial guess is a crossed hot wire, but again, I don't have much in the way of education on this truck.



A previous owner has installed a lock-up switch, but I don't know much about the wiring of the transmission to know whether it was done properly or if it is causing this problem.



Thanks.

 

[NKenny]

Help me please :{ !

 

[Joe G.]

I really can't say much. The symptem sounds like a TPS problem, but I can't really say since there is no way to know how the lockup switch was done.

 

[NKenny]

I really can't say much. The symptem sounds like a TPS problem, but I can't really say since there is no way to know how the lockup switch was done.

Good Point. I will dig into the Lock-up switch and try to trouble shoot there. What other symptoms would be associated with TPS malfunction?



Thanks.

 

[Joe G.]

If the TPS has a problem it will be sending bad information to the PCM about where the throttle is. So anything that the PCM controls (OD and TCC lockup) may do funny things. There are different ways of wiring up the lockup switch. Here is the basic set up: http://www.tstproducts.com/Torque Converter Lockup Switch.pdf At least you know which wires go where from that. If you don't have a service manual you should get one. If the PO did the lock up switch in some "custom" way you may need the wiring diagrams to figure it out.