Engine/Transmission (1994 - 1998) TSB concerning auto trans?

[RKraiza]

I'm haveing a problem with an apparent engine miss that I previously posted. Has anyone ever herd of a possable TSB or condition concerning the torque converter locking and unlocking, simulating a engine miss at around 12oo rpm?

 

[AHughes]

I had a similar problem and traced it down to the crank position sensor. It's an easy fix just remove the starter the three 10 mm bolts are a bear to get out (I replaced mine with metric socket head cap screws) and the sensor is in the block behind and I think above the starter? Can't remember exactly (old age I guess?) It's held in with a clamp with one bolt on it and just a 2 wire plug in. I got mine from Cummins Northwest and it was (I think $55 including shipping) and a $9. 00 core charge. They'll refund the core charge upon return of the old sensor. The sensor just pushes in the block and is sealed by an "O" ring included with the new sensor. I put some grease on the O ring and pushed it in the block installed the bolt and plugged in the wire connector. Viola!! it did the trick. You might want to, while you have the starter out, install "Larry-"B's" contacts in the starter as well. They're about $35. 00 and it's a good time to do it. You can fix both for about $100. If that's not the problem you are probably getting electrical signals that are affecting the shifting and lockup of the conveter. Call Stephan at Diesel Transmission Technology in BC Canada. They sell a noise filter that's an easy install (2 wires) for about $40 US that will filter out the electrical noise that might be causing your converter to lock and unlock. This filter fixed my lock/unlock problem after trying the reflash etc. . Make sure all your electrical plugs and connectors are clean and I put dielectric grease on all mine as they treat the roads up here in the winter with Magnesium Chloride and it will rust the fillings in your teeth if exposed to it. They say it doesn't but I have fisheyes in my stainless panels on the lower body of my truck from this stuff. Hope this helps. AHughes Bend Oregon. 98. 5 3/4T QC 4whl drive. DSS, F1 injectors, Edge Comp, Leer Canopy, AFE.

 

[Joe G.]

RKraiza,



I don't think your '96 has a crank position sensor. You should update your sig to show what kind of truck you are driving.



I had a problem with my '95 that was hard to reproduce that acted like an engine miss. It would only do it in certain conditions when my camper was on board or I was pulling my trailer. The symptom was a very hard hammering jerking that appeared to be an engine miss. It was NOT an engine miss at all. It was the torque convertor locking and unlocking. This can wreck your flex plate. That happened to me. $1500 for the dealer to fix. Since then I have learned how to fix things on my truck myself. The problem was caused by a dirty TPS.

 

[RKraiza]

You nailed it on the head! That is exactly what my truck is doing! You have me convinced it's definatly the torque convertor locking and unlocking. Now, could you point me in the direction of diagnoseing the TPS or othere possable causes before I rip the transmission out? Is disconting the sensor an option in diagnosing the convertor? Thank's

 

[Joe G.]

You had me a little fooled on the other thread with a description as a miss. Sometimes these TCC lock and unlock problems are stubborn, especially on a '96 for some reason. There have been cases where replacing the TPS did not solve the problem. Some people have taken the TPS apart and cleaned it. Other times just hoseing the TPS down with contact cleaner and working the throttle linkage back and forth will fix it. That's the first thing to try. If that does not work, pull the wires out of the harness for as far back as you can and see if that helps. Let us know how you make out. It may take some patience to fix it.

 

[RKraiza]

I'm ready to convert to Ford!! replaced the TPS and installed a mystery switch. The engine is skipping under load which I cannot duplicate unless towing. Thnaks for the help and insite but I now feel it is once again a fuel issue and will refer to my othere thread posted "engine miss" from now on.