Engine/Transmission (1994 - 1998) 47RH torque converter not locking up - Chapter 2

[Sojourner]

Last May I experienced this problem of no torque converter lockup along with a higher shift point into third under less than WOT. The local dealer which has always taken care of business (primarily 'cause I had a good relationship with the service manager who is no longer there) had one of their 'techs' screw around with it for a week (replacing the throttle linkage and cable at no charge to me due to a complete misdiagnosis) before their transmission guy got his hands on it whereby he determined that the tab that actuates the TPS was somehow pushing the guts out of the TPS housing (I saw the TPS after this had occurred and there isn't much protrusion out of the TPS housing itself). Supposedly they had done what was necessary to eliminate this problem. Well, the exact same problem of no TC lockup is back and I'm relatively certain that it is the same problem with the TPS getting broken by the actuator.



Has anyone else experienced this problem of the tab that actuates the TPS breaking it by pushing the guts out the opposite side of it?



TIA!

 

[Joe G.]

The TPS is a variable resistor. Simple gadget. You can check it with a meter. If it is working properly the "pushing the guts out" thing is just a fairy tale.

 

[Turbo Thom]

I did have a "tab" that was broken off. Had to replace the TPS and all is well.

 

[Sojourner]

The TPS is a variable resistor. Simple gadget. You can check it with a meter. If it is working properly the "pushing the guts out" thing is just a fairy tale.

Yeah that's right, but if ya break the thing it simply isn't going to work. What I saw was a new TPS that was broken (pushed out ever so slightly on the side opposite the actuator), the one they installed which was broken after a test drive.



Joe, I just emailed you an image of the exact TPS I'm referring to. Please tell me what you think.



I just had one of the service advisors pull up the invoice corresponding to this episode and the only thing that was on the invoice parts-wise with respect to this problem last May-early June was the TPS. Could this problem have to do with the TPS mounting bracket? At that time I had asked what they had done to correct this problem and they alluded to something about shimming the TPS and/or the TPS mounting bracket as I recall (I had directed them to replace the TPS mounting bracket if that was what it would take to eliminate the problem and for some reason which I didn't understand I was advised that replacing the TPS mounting bracket would not solve the problem).



Over the past three or four weeks I have noted only a handful of incidents/indications here and there that there was no TC lockup but it never persisted. What other condition would lead to no TC lockup? It sure seems to behave the same way as before.



Edited to add: The dealer replaced the TPS in Nov. '04 and the truck was driven less than 10k miles in the interim, so the replacement of the TPS in May of last year was under warranty.

 

[Joe G.]

I repliled to your email. Kind of slow since I was in town for a while. If the TPS is working then you need to find out if the PCM is grounding your TC lockup solenoid. Hook a meter up and take it for a drive. It should show 12 volts on the wire to the connector until the PCM puts a ground on it. If it grounds the solenoid properly and it does not lock up then you have a problem involving the VB. Maybe a bad solenoid. Anyway, you need to do some trouble shooting. Sometimes a 47RH will lockup if you lift when it's up to speed and then press on the loud pedal again. See if that helps. You need to find out what is happening. Just throwing parts at it and hopeing the problem goes away can get expensive and frustrating.