Engine/Transmission (1998.5 - 2002) Torque Converter Lock Unlock

[BMelhuish]

I know this is an old and much discussed issue, and I have been down this road before. Several years ago I had this issue when I was going about 35 mph and at 1500-1700 rpms. I have removed the wire from the alternator harness and for other reasons about a year ago the alternator was replaced with a new alternator. I also had a loose ground terminal on the driver's side battery. No continuing issues.

Last week I went on a trip with my 5th wheel with no issues to my destination or while I was there. In coming home at 65-70 mph and 2100-2200 rpms, the TC would unlock and the rpms would jump to 2400-2500. It seemed to get a little worse the longer I drove-it would last longer. I only had a 100 miles to go so I just continued home.

Is this the same issue just at a different speed? I am not throwing any codes. The driver's side battery is 4-5 years old and could be bad, and I haven't had a chance to test it. Can this cause the problem if it is lock up issue? Finally, there was an article in the TR. Does anyone remember the issue number?

Thanks.

 

[JR]

The underlying issue that you tried to correct by removing wires from the harness was very likely bad diodes in the altenator putting out A/C voltage. There are lots of bandaid fixes for this but the only real fix is to test for AC voltage and replace the altenator if necessary. Test the output of your altenator with a multimeter set to AC, it should be running less than 0.1 volts AC with the engine running. Another way you can test is to pull the main altenator fuse in the PDC and go for a quick drive. If the truck doesn't act up youve likely found your problem. Just dont go for too long a drive and keep all the accessories to a minimum as you'll be running off battery power only.
Depending on the type of altenator you bought you could be very well looking at the same issue again. Reman parts are really hit and miss from my experiences, particularly the last 2-3 years.

 

[BMelhuish]

Thanks. I finally located in my files the TSB given to me by Dodge on the issue. 18-02-99. Although my symptoms were different at the time, the current symptoms match the TSB. No. 1 and 2 are the battery condition and connections and the alternator with the problem being either noise from the APPS or the alternator. The alternator is only about a year old. Thanks.

 

[JR]

If you have a multimeter I would definitely test the altenator anyhow. Its free and still a very likely culprit. New (reman) alternators have failed the AC voltage test right out of the box.
Didn't think to mention grounds and battery connections but that along with load testing batteries is a good idea.

If neither of those pan out you could do an APPS reset to see if it temporarily cures the drivability issues but I've not seen an APPS cause actual lock up issues. Driveability issues yes but I'm not sure about the lock/unlock symptoms.

 

[BMelhuish]

JR, I'll do that. As an aside last time I moved the alternator wire and found a loose ground terminal on the driver's side battery. I don't know which one solved the issue, but it's been good for almost 2 years. I'm convinced that it was the ground. The alternator was replaced later for other unrelated reasons. Since I didn't do it, I have no idea if it is new or reman. In the past resetting the APPS did temporarily solve the issue. Becasue I just got home, I haven't had time to do much other than check to see if it was throwing any codes. Thanks.

 

[BMelhuish]

JR. Quick question on the alternator check. Am I just checking the alternator at the battery for just output or the ground resistance circuit or some other way? Is this something that will show up only or vary at higher rpms >2000 or under load?

 

[BMelhuish]

JR. Turned out to be the alternator. It tested out at over .1 AC. The shop were it last took a dump replaced it with one of those finely crafted Chinese POS. So, I replaced it with another from Autozone. At least it has a life time warranty. Thanks for your help.

Blake

 

[JR]

Thanks for the update! I'm sorry I missed your last question, I never got a notification. It sounds like you figured it out and all is well now. Good deal. Unfortunately this is all too common with reman parts anymore. Companies use the cheapest components possible to lower the bottom line and what you get is an inferior product. At least you got it fixed (the right way).

 

[BMelhuish]

No worries. The one that I replaced today was a new, not reman, unit. I took your advice and installed another "new" one. Thanks.

 

[Bob4x4]

Contact DTT they have a filter that will fix 99% of trucks

 

[JR]

The noise filter thing seems like more of a band aid fix then anything to me.

 

[BMelhuish]

A while ago there was an article in the TDR that laid out a hierarchy of the sources of the problems. The TSB I mentioned above does the same thing. I didn't mind taking the wire out of the harness and rerouting it. It didn't hurt or change anything to do that. Other than that my belief is that you will be better served by finding the source of the issue and correcting it rather than trying to cover it up with a fix that costs as much as the part to fix the problem.

Now, I do realize that not all of the members here have the ability or knowledge to work on their vehicles. In that case this can be an expensive problem to fix if you are paying an hourly rate. Under those circumstances, a bandaid may be an attractive less expensive alternative-if it works (I've not tried it and cannot express an opinion). However, I do appreciate the reference.

 

[Struttin40]

my 2000 does it around 30 then again at 45 really bad,it will drive you crazy lock unlock lock unlock as long as you hold those speeds.I have covered the ground wires with foil but it only lasted about 3 months,I tried the disconnecting of the fuse under the hood but it continues to do it,I may just replace the alternator anyway,Don

 

[BMelhuish]

Don:

If you go to Geno's website, they have the TSB I mentioned. If you're convinced the grounds are good and the batteries are ok, test the alternator for AC current. If you have more than .1 as mentioned by JR, you have a bad diode in the alternator. Replace the alternator. The test is easy to do with a digital voltmeter. Just set it for AC current and test at the battery. It will jump around, but if it goes over .1, you'll need that alternator. I also reset the APPS when I was done.