Engine/Transmission (1998.5 - 2002) Can't stop transmission from hunting in and out of lockup.....

[hammersley]

Tried everything..... but obviously missing something. At 37-40 (3rd gear) and at 52-55 (4th gear) the transmission will go in and out of lockup repeatedly. The alternator wires have been wrapped for years. We thought it was a bad ground at the battery... . the cable has a non factory end that was loose... we fixed that. Serviced the transmission - everything was good... replaced the APPS assembly with the new HD one..... no luck..... HELP.....

 

[Regcabguy]

I tried everything on the '98. 5. The DTT noise filter permanently cured it. I lucked out.

 

[macdaddy]

Is it throwing codes?



Might be the TPS?



Mac

 

[rasteck]

Lots of good info here:

TC lock up thread - Dodge Cummins Diesel Forum



Lots of different cures and there doesn't seem to be one that works for everybody.



I added the lock up switch this week so I could lock it earlier to keep the heat down when climbing steep mountain roads and towing. I left the relay in and used a 33ohm resister to ground via a switch from the B11 wire described in the link. No CEL that way.



TC switch howto (with pics) - Dodge Cummins Diesel Forum



Good luck!

 

[cerberusiam]

The alternator wires have been wrapped for years.

Unwrap them, cut the ground wire and charge wire out of the existing harness and reroute them seprately. Ground wire along the firewall to the 4 way split in the harness and the charge wire over the radiator support will eliminate 99% of the TC lockup issues.



The rest of them are a bit more difficult to track down and may never be completely cured. Rerouting the wires has the highest success rate of any fix so you might as well start with something that works.



Good luck, it is ANNOYING.

 

[hammersley]

Will try do you have any PHOTOS

of the actual rewiring ?

 

[cerberusiam]

I don't have any pictures, sorry. Its all wrapped up now so that doesn't help.



My son did it and he actually pulled the ground wire completely out of the harness then just extended it so he could route it along the firewall instead in the ECM\PCM harness.



The same with the charge wire from the alternator, routed it in plastic conduit across the top of the radiator and back to the same anchor point by the fuse box.

 

[hammersley]

WOW - what great advice.....changine the route of

I don't have any pictures, sorry. Its all wrapped up now so that doesn't help.



My son did it and he actually pulled the ground wire completely out of the harness then just extended it so he could route it along the firewall instead in the ECM\PCM harness.



The same with the charge wire from the alternator, routed it in plastic conduit across the top of the radiator and back to the same anchor point by the fuse box.

the charge wire seemed to solve this... ... nothing else worked. Now what doesn't seem to make sense is why after 360,000 miles did that all of a sudden develop? Years ago I had the aluminum foil shielding done on the harness near the alternator..... and everything was great. But what actually had changed to make the rerouting not only necessary BUT that it actually worked... . seems a mystery... . But anyway thanks a million...

 

[cerberusiam]

Deterioration of the shielding in the wire and even in the alternator is the usual culprit. The frequency changed just enough to setup a different type of noise that the shielding could not filter. Same with the PCM, age deteriorates the ability to filter specifically and stray noise begins to make more of an impact.



Its the unfortunate truth is that eventually the electronics deteriorate to the point where they may just not work and then the truck is unusable. :{



As I have said before, all the filters and tin foil will not stop the problem. It eventually comes back when the frequency changes enough to impact the PCM as it ages. The ground wire is the usual culprit but as uou have seen the charge wire can dirty things up also. Glad it worked for you.

 

[Nyoest]

Or change your fuel filters. Seriously if they are partially clogged the truck can't make proper torque to stay locked up esp at lower speeds. It worked for a friend, odd thing is the truck seemed to run fine.