Got a question regarding the Lock-up torque converters in the early Dodge automatics. I've purchased a 1992 3/4 ton club cab with an automatic behind a Cummins diesel in July 1992. I've got about 122,000 miles on the truck now. The diesel has given me NO problems whatsoever. The auto trans has been a headache for years. Dodge has rebuilt the trans twice, both times under warranty and now I've had it rebuilt once again, paid for out of my pocket. Both times Dodge rebuilt it the trans shop had found metal shavings in the pan when I took it in for tranny fluid change. No questions asked by Dodge, they just said OK, and rebuilt it. Now I'm having problems with it dropping out of overdrive (the torque converter unlocking and dropping back into high gear) The latest was about a week ago when it did it again and the voltage dropped from 14volts to approx 12volts and stayed there. I had just replaced the alternator and had checked the voltage as indicated on the dash-mounted volt meter.

The voltage is staying at what appears to be 12volts indicated and the tranny will not let the torque converter lock up.

What's going on?? How do I fix what's wrong??

 

Your truck does not have a lockup convertor, they came along with the 2nd gens. Your truck is dropping out of overdrive (a seperate gear in the trans). This is controlled by a number of sensors, but since you are having charging issues also I would check the crankshaft position sensor and it's harness. The sensor is located by the harmonic balancer and has a plug in connector by the no.1 valve cover. Mine came unplugged and I lost OD, charging, and A/C.

 

Dodgestein, I'll check that first. I did loose my AC on two occasions for no apparent reason AND I did have a charging problem that seems to have come back. THANKS!!

 

Alternator/voltage issues will also affect the TPS. It has a baseline voltage on which the shift point from 3-4, and 4-3 is governed, to some extent.
If you have fluctuating supply then the "sweep voltage" will be affected. It doesn't take much to change the shift point.

Metal shavings is another thing altogether. If you're getting that every time then something is either installed wrong, worn or out of tolerance. Some very fine filings are common. You will have fibre from the clutch disks, and some silver shavings, likely alum. as well.
Hopefully your oil cooling lines/system is not contaminated or you'll be doing tranny work till the cow starts talking...

Pastor bob.

 

As mentioned above. Many things effect OD. I would also check your Tranny Temp sending unit. It is located just in front of the oil pan. Clean that very well if possible. If the tranny isn't up to the proper temp (about 100 degrees) it will kick it out of OD. With this past cold snap in VT (-20 to -30 BELOW zero). Even driving around and truck is warm up, it would kick out some times due to idling and letting truck cool down for a few minutes. Also check your TPS. They are known to fail or get dirty. That should read a Idle (engine off) with key ON about 1 volt + or -. Then you should give it WOT (again, engine off) and it should bring it up another 2.75 volts or so. Check by using the MIDDLE wire on the TPS. Crank sensor, make sure it is clean and connection (by tps) is connected good. Should only be about a Matchbook cover from the Harmonic Balancer (don't have exact right now). Also check your Tranny kickdown cable. That is located by your throttle cable and has a little clip to loosen it up. Be careful though as it doesn't take much to adjust and it will screw things up if mis-adjusted. With engine off, you should be able to give it WOT and notice that the kickdown cable moves your tranny to full position. Then you should only have about 1/8 - 1/4 inch of extra push to be at WOT position at the Tranny location. This adjusts when it wants to kick down but mostly adjusts your Line Pressure.

Hope this helps.

 

Thanks for all the info. I'll check all of them for sure. What I can't understand is why would the voltage suddenly drop from 14v down to about 12? The only time I have ever seen it do that is when the air preheater kicks in. Then the voltage would go back up as it cycled off and on. Now the voltage is staying down.

Any ideas? It acts like something is pulling the voltage down and not letting go. A shifting solenoid pulled back and not releasing?

 

I have seen my voltage gauge be in different spots for some unknown reason now and then. When my preheaters turn on, mine drops very low, like almost off the gauge but comes back to normal when the light goes out. Maybe a close Auto store (Napa, advanced auto) may have a tester. They brought theirs out to test my altenator and it looked normal when I noticed my gauge dropping. It may be a bad Ground some where possibly also. That would possibly ground the whole system out.

 

Well guys, I checked everything that was suggested, if I could. I found nothing amiss so I said to heck with it and decided to let Dodge have a go at it. I fired up the truck and by the time I had gone two blocks, the indicated voltage was back up to 14 volts and all the way out to Dodge (about 5-10 miles) the tranny shifted into and out of overdrive correctly. Guess I shouldn't have said I was going to let Dodge work on it while within earshot of the truck.

 

I agree. The truck heard you and won't fail now for a couple of weeks. Then it won't work for another week or so. This will go on for the rest of the season until it is summer time. Then it will fail once and for all, when you need it the most to cruise around with.

 

Well guys, $628.00 later, I got my truck back from Dodge and it's going to work properly. ........... I hope. The TPS and VSS were both shot. What's a VSS??

 

Mike;
The Vehicle Speed Sensor is located in the tail housing of the tranny.

ramguy

 

My OD starting dropping out around 55 when I left off the fuel pusher pedal and engaged back in when pushing the pedal. I read the following post and other posts about setting the TPS by the electrical current at idle and WOT and bingo!!

It works perfect again, thanks guys keep up the good work. Come to the Carolinas for some great hospitality, football, barbecue, and a lot of appreciation someday.