Engine/Transmission (1998.5 - 2002) Torque converter unlocking/locking

[CaptainEric]

My torque converter randomly unlocks under 50 MPH. The PCM was flashed 2 years ago for this problem and it worked until last month. The dealer has had the truck 2 days and cannot find the source of the problem, other that to say it is electrical related. Mechanically the trans is ok. Other the the TPS and PCM, what other areas might cause a voltage spike that would cause the transmission controls to unlock the torque converter? Two months ago this happened and all we did was remove and clean the battery terminals and the problem went away. Not this time. Tomorrow I am going to disconnect all the electrical accessories that I have added just to rule them out.



Suggestions, comments, ideas. I am willing to try just about anything at this point.



1998 24V 47RE 3. 54 rear

 

[bmoeller]

Could be the TPS. At least on the 12v trucks, they can be cleaned with eletrical contact cleaner.

 

[Tom W]

Sounds like the same old problem of electrical noise spikes, Cleaning the battery terminals is a temporary fix. I fought this problem for over a year and finally fixed it with a DTT noise filter.



Call DTT 1 866 504 4002

 

[Extreme1]

I doubt this is it but it's worth a shot. If it drops lock up but not the cruise this isn't it.



Adjust the brake light switch by pushing down on the pedal and pulling on the switch contact towards the pedal. They ratched out. It will ratchet back in to the correct spot when you release the brake pedal.

 

[CaptainEric]

Contacted DTT today and ordered the noise filter. The tech was very helpful in explaining how the filter connects, as well as other ares to address to get the best results. In short, remove and clean all connections from the battery at both ends of the cables. Remove both the PCM and ECM and clean the contact points where they mount to the fire wall and engine. Also run a ground strap (ready made) from the fender ground where the battery connects then direct to the PCM ground. All of this is to ensure the best possible grounds everywhere. They estimate about 4 hours work.



Hope to do some or all of this over the weekend. Thanks for everyones help so far. I will update with my progress.

 

[CaptainEric]

Update

Update... On Thursday, I unplugged and cleaned the gray connector between the battery on right side, negative post, and the PCM. There is another gray connector in the same location that disappears into the alternator wire harness. I disconnected and cleaned that one too. Driving the truck Friday there were no problems with TC unlocking.



Saturday I decided to go ahead and install the DTT Noise Filter and clean all ground connections I could get to. On PCM connector C1 pin 23 is the orange/blue wire from the throttle position sensor signal wire. This is where the noise filter is to tap into. When I unplugged this connector to verify I had the correct wire, I found the insulation cut about an inch from the back of the connector, inside the protective cover.



I called my dealer to see if Dodge will be willing to correct problem at minimal cost but will have to wait till next week for them to contact the factory. In the meantime I did not install the filter, not wanting to disturb the wiring. I did go ahead and clean grounds and the PCM mounting points, as well as install an additional ground wire from the battery fender ground connection to the PCM.



Driving the truck this afternoon it still drives ok, no TC unlock.

 

[Tom W]

Looks like an easy fix. why mess with the dealer?

 

[John - K5AWO]

Why go to dealer- I agree:



Trim it back a bit, look for broken strands. If none found, add a little solder to the open area and seal it up good.



Don't use tape, mositure gets under it and stays there. Battery post grease (Noxid) is fantastic for preventing moisture and corrosion. Bit messy though and needs to be covered.



Were it my truck, I would cut the wire. Remove about 3/8" insulation both ways. Slip some heatshrink over the wire from the harness (trim back the outter jacket of the bundle).



Twist wires together, solder with a high quality solder. slide heat shrink down over the joint and seal it up.



You mentioned that is where the noise filter taps into. Tie it in before the heat shrink goes on. Put some battery post grease on the joint (just a dab to cover the joint. not over the insulation).



Then heatshrink it.



Get the battery post grease from AutoZone or other parts outlet.

 

[Joe G.]

Heat shrink tape is available that seals as good as the tubes. You don't have to cut and solder the wires to use it.

 

[Bob4x4]

Looks like someone was already there playing(testing?)that is not a factory installed cut Good luck,I have done plenty of these issues and have to listen to customers not beleiving some of the causes. It can be time consuming so if you are patient and methodical you will fix it.



Bob

 

[CaptainEric]

So far so good, not one unscheduled unlock/lockup of converter since cleaning grounds, about 500 miles of driving. What I have done so far... .



1. Cleaned gray connectors between battery (passenger side) negative terminal to PCM, and gray connector from same battery negative terminal to alternator.

2. Cleaned and sealed grounds from both batteries to fenders.

3. Removed and cleaned all connections on both batteries

4. Added ground strap from fender ground connection to PCM.

5. Removed and cleaned PCM mounting points for better grounds.



I used a spray can of electrical terminal cleaner and dielectric grease on all connections for cleaning and reassembly. Then I applied Liquid Electrical Tape by Star brite to seal all connections. I have used this tape for years on boats and it works great for keeping connections clean, even near the coast.



I have the noise filter from DTT but have not installed it yet.



As far as the cut in the TPS signal wire in picture above, that was done by the technician at the dealership. This is where he tapped into the TPS to check operation and where he registered the spike in voltage.



Thanks for everyones help. Lets hope this solves the problem long term.

 

[OTRPU]

CaptainEric, If you decide not to use the filter I'd like to take it off your hands. Maybe, just maybe I have this same problem. Have been blaming it on my ATS TransCommand box. They just replaced the box with latest version. Today, running from Chanute, KS to Rawlins, WY enroute to Murray, UT, driving along, flat terrain, no wind, no heat, (transmission temp 135*F), pulling a 5er but no strain. . . the TC unlocks. I mean like I'm locked in cruise, 65 MPH, OD on, just going for a ride. It unlocks, then later it locks back up. Had heard evidence of it doing this a couple times earlier, but didn't actually extinguish the TC lock diode on the TransCommand. This time it did. I don't like spooks and gremlins in my ride. Let me know if you want to sell the filter.



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Cheers,

Steve J

 

[Big_Daddy_T]

Sometimes replacing the batteries helps too.