Okay, First off, I have searched these and other forums.

Now, some background. I bought a 2000 Dakota R/T about 6 months back. 107K miles. It has had transmission issues since I bought it. The things I noticed right away were that it would not shift out of 1st gear during WOT. I researched this and adjusted the cable. No dice. By the time it would shift at WOT, it would then shift 2-3 at 3600 RPM. After more research I replaced the speed sensor in the tranny. This did not solve the problem either. I truck had a few bolt-ons and I suspected the computer may have been flashed at some point. I had an PCM from a 2001 Ram with a 5.9 from my last truck laying on the shelf. I put it in and bingo, the trans shifted normally at WOT. It however, did cause the brake and ABS lights to come on. I didnt want to run the truck with this PCM.

I just said screw it, and just let off the gas for a quick second to make it shift into 2nd. I then notice a few days later that the converter locks/unlocks extremely easily under light load. I have a 2 mile road that has a 30 mph speed limit that I have to drive to get out of my neighborhood everyday. It continually locks and unlocks over and over trying to stay at 30 mph. At all other speeds, I didnt notice any problems.

Well, I'm driving at 60 mph down the road one day and notice that the converter is not locking up at all anymore. About 30 minutes later, the O/D turns off, shortly followed by the trans temp light. I pull over, let it cool down in neutral running, check the fluid (clean, red, correct level), then drive it home. I know the O/D off and trans temp are being caused by heat from the TC not locking up. The check valve in the coolant lines has been removed as well by the previous owner.

I took the truck to a shop that specializes in mopar vehicles. They hooked it up to their diagnostic computers. They told me there were no fault codes and that the PCM was telling the TC to lock when it should. They told me it was probably the torque converter clutch and I needed to rebuild the trans because of all the crap that was in the fluid (bits of clutch material they said.) The fluid in it by this time is brown and smells burnt. I dont see any debris in it though. They said I MAY be able to get by just replacing the converter, but it probably would need a full rebuild.

From my research, I have read about how the TCC solonoid could possibly be the problem. I dont understand how replacing the converter alone could be a possible fix. Are the clutches for lockup located inside the converter? Since I still have all forward gears and reverse, do I really need a full rebuild? Does anyone have any further suggestions or other things I can do to further troubleshoot this? Im afraid to drive the truck like this because the heat is killing any little bit of life this trans may have left. This is however, my only vehicle and is my DD.

Thanks!

 

Okay, maybe that is too much for people to read. so here is my very short version...

Torque converter doesnt lock up anymore. what are the most likely causes?

 

Here is a good read.
https://dodgeforum.com/forum/1st-gen...agnostics.html
may be overdrive Solenoid or converter clutch solenoid.

 

Yes they are. Once they start to slip, they don't last long.

How are the line pressures? Any transmission fault codes? A regular code reader won't read them. A DRBIII can read faults and the line codes as the vehicle is operating.

 

I had taken the truck to a local shop that scanned it while driving. There were no fault codes. they didnt tell me what the pressures were. They said the PCM was telling it to lock up though. they said it was the converter, but that i would need a full rebuild for 1800 bucks. The reason i question this is because i know my truck well and i never noticed it slip at all. It was just like someone turned off a light switch and the converter wouldnt lock. after research, i found out about the TCC solonoid. it just seemed more logical to me that this may be the issue since it was super sudden. that along with the fact that the converter loved to lock/unlock over and over at light throttle and slow speeds. ~30 mph or so.

 

The thing about the TCC solenoid is that the pressures are monitored. There are pressure switches in the system that help the TCM determine if a failure occurs. Since you aren't getting any faults, the likelihood is that it is the converter itself.

You may not notice the torque converter clutch slipping. Years ago cars didn't have them at all. It's only the high transmission temp that's the clue that something isn't right. A slipping TC clutch will cause high temps. It's supposed to lock up from 3rd on up.

I know some people do remove the check valve for the cooler, I don't know if it's a good idea. The fluid will drain back from the converter when sitting for a time and then it needs to refill on start.

You can always get a second opinion. Again, it should set a code if there is a problem with the TCC solenoid.