hey gang, having problems with my stock 95 4wd 12 valve. Had another tranny in it & it did the same thing, put that tranny in another truck & it worked fine. Put another tranny back in the 95 & it did it again, so....its something in this 95.
I don't have OD or lockup; took it to an electrical repair shop, & he verified power / current's integrity from the computer all thru the wiring back to the tranny (plug).
Maybe its something inside the tranny? but maybe not because it did it with the prev tranny too. Not sure if maybe the plug in / receptacle ON the tranny where the 3 prong plugs in is malfunctioning either. Another mechanic grounded out the plug with a toggle switch & got it to lockup on the hgihway, so its been in & out of a few shops over the last year & I've lost track of 'this worked but that didn't', etc.

Any suggestions?? Thanks for your help

 

i had that prob with my 2nd gen auto converter locking and unlocking at will. had a shop look at it they added a voltage capacitor to the electrical system to help keep the voltage steady at 5 volts. if you want to try it i will look tommorow and see where it is exactly.

 

I used to have the Tc unlock problem with my 95 . I installed a switch on the dash and use that while towing. It won`t unlock the TC till I want it to unlock.The truck is much better for towing . later Don

 

Bad brake light switch, tranny temp sender or TPS are the main things that prevent lockup.
You can always install a lockup switch, simple and cheap.
Instructions> http://www.tstproducts.com/Torque%20...p%20Switch.pdf

 

tps or brake light switch .

 

x3. My money will be on the TPS.

 

I vote for manual switches! i like the control.

 

on my 94 mine searches aswell. i have noticed when my break lite and emg brake lit is on. it actes up more.. but when it goes out. it tries to stay locked longer, but still searches.. i have read on anouther forum to wrap the wires that are on th alt bracket with foyel and blk tape.. i have not tried this yet.. nut will try ,,

 

thanks; I will check these. However I don't have OD also. Lockup is not on & off; it won't lockup at all to begin with. Does that change any diagnoses?
(I was going to put a mystery switch in it, but would rather have it work like 'normal' as I plan on selling it as soon as I can get it fixed.)
Thanks

 

where is the tps located?

 

TPS is located on the drivers side of the injection pump...a little black plastic square that causes nothing but misery! Do a search with my username, you'll find lots of info.

Like others have said, the TPS is most likely the culprit. Easiest way to verify whether your TPS is getting the correct voltage is to get a voltmeter and backprobe the three prong connector.

To double check the brake light switch function, wedge your foot underneath the brake pedal and pull up while driving. If you still don't have OD/lockup then your brake switch is not causing the problem.

cj360trider has some good posts on a 1000 ohm resistor to trick the tranny temp sensor.

Also, infidel has posted tons of info on this and a million other tips that will help you out.

Hope that helps.

 

Click> Throttle Position Sensor Testing/Adjustment