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

[JUrish]

This is the second post--I think the website ate the 1st one.



As of 2 days ago my '01 has began locking/unlocking the torque converter under light throttle. The problem goes away after you hit 55.



The problem is shown by what feels like engine surging and a 100-250RPM change in engine speed. It sounds like the engine loading and unloading.



Any ideas on where to start looking?

 

[AKAMAC]

DTT sells a filter to eliminate this problem. I'm sure you've seen the name mentioned here often. Give the Canuks a call... ... Mike

 

[JUrish]

help me here. . I have no idea what you are talking about. . I don't think there is a rule prohibiting naming names. .

 

[cerberusiam]

The TC lock\unlock is some times caused by noise generated in the electrical system by the alternator. It manifests itself at certain positions on the APPS and interferes with the signal read by the PCM to control the TC lockup. Hence you get the hunting at certain pedal positions.



There are a couple of ways to fix it. One way is order a premade filter kit from Diesel Transmissions Technologies (aka DTT) in British Columbia, Canada.

Here is their link http://www.dieseltrans.com . The filter will clean up the signal that is used to determine TC lockup and in most cases will solve the problem.



You can also solve the problem by finding the wirre in the harness that runs from the APPS to the PCM and route it in its own loom away from the other wires. If it is noise from the alternator that will most times solve the problem also. If you feel really ambitious you could also build yourself a filter with some components from Radio Shack.



Before spending time and $$ you might want to try a few things and see what happens.



1. Check all grounds for contact and use dielectric grease on them.



2. Check both battteries and make sure they will hold a load.



3. Reset the APPS.



4. Check your harness connections between APPS and PCM.



Some times the above works and problem solved. Other times its on to the next step and either use an external controller or try the filter route. Either way its what happens when you stick low voltage computer equipment under the hood of a diesel truck. Some times things don't work as planned. Good luck.

 

[JUrish]

Cool thanks! I will do that this weekend. . I bet something has just loosened up. .

 

[RacinDuallie]

First thing I would try is to disconnect neg. cables for 1/2 hour to 1 hour then Reset the APPS
If you still experience problems then you probally need the filter... ... ... .

 

[tractorface]

Right on Racin Dullie

Reset the APPS. Just had the same problem, made the truck miserable to drive. Called Dave Goerend and he sent me a filter but old me to reset the APPS cause that should do it. Tried disconnecting the batteries for 2 hours and did the reset with only fair results still had the problem only a litttle less. Unhooked the batteries overnight and reset the APPS and WALA All better, really hard to believe but I'll still install the filter eventually. Reset that APPS and don't forget to do it eveytime you discect the batterie for whatever reason

 

[smokejunkie]

What is the APPS?

 

[Joe Mc]

APPS = Accelerator Pedal Position Sensor. Some auto manus call it TPS = throttle ps etc.

 

[SDonald]

I also had this same problem on my 1998. 5 going in and out of lockup. This was a very annoying problem that I couldn't afford to deal with for almost 2 months and then, on its own, suddenly quit and hasn't done this in about 4 months. Now I have some hesitation when first accellerating and slippage into 2nd when taking off hard. Should I break down and get the new convertor and a rebuild?

 

[GordonG]

Was wondering what you ended up doing about the APPS? My '01 appears to be having the same problem.

 

[rweis]

I am going to recalibrate my APPS next week (spring break). The procedure is on the DTT site. Basically you measure the APPS voltage on C1 over by the passenger side firewall closest to the engine with the key on.



Then take the APPS apart until you find the TAG that has what the voltage is SUPPOSE to be. If it is different then loosen the two screws and rotate the APPS until it is very close. READ the procedure though because there are a couple of GOTCHA things you can screw up.



Bob Weis