Transmission hunting/torque converter....

[Reluctant Mechanic]

1999 2500 QC 4x4

Only changes from stock currently are a sending unit on the fuel filter canister for a FP gauge and a FASS DDRP. Had a gauge going for transmission temp but that isn't working. Also rebuilt the battery terminal clamps, replaced the positive cable going between batteries with soldered ends and replacement clamps.

I have been chasing a transmission hunting issue for years. I can't remember when it began, if it was after
the battery cable rebuild or not, but my understanding is that it is caused by ground noise. In the past I cleaned all the grounds, battery tops, connectors etc, and new batteries also fixed the problem...for awhile.
It tends to hunt at 45-50 mph but is fine over 55. Unfortunately the roads around where I live have 45 MPH speed limits, really annoying!

This week we relocated G-100 because the bolt was frozen no matter what and my past efforts to get the nut off torqued it and it seemed like it was going to break. The move didn't improve the hunting, unfortunately.

I was reading up on alternator noise causing torque converter issues. MoparMan has an article about how to test the alternator to see if that's the source of the problem. We did replace the alternator before this issue appeared so there may be something there. I am going to pursue this testing.

What I'm wondering is, is there a poll or article listing all the known sources of noise that can cause this torque converter hunting issue?

 

[Ozymandias]

It's a simple AC test at the Alternator to see how well the rectifier works.

 

[petersonj]

Are you familiar with the W-T ground reference wiring modification for the VP44 trucks? It essentially provides the most direct routing for ground wiring of the the PCM, ECM, and VP44. Also, included is rewiring the alternator output wire to the passenger side battery. This information can be found on the Moparman site.

If there are ground problems on your truck, these can cause excessive AC voltage ripples in the charging system. I recommend doing the W-T ground wiring mod before testing the alternator for AC voltage.

- John

 

[Reluctant Mechanic]

Are you familiar with the W-T ground reference wiring modification for the VP44 trucks? It essentially provides the most direct routing for ground wiring of the the PCM, ECM, and VP44. Also, included is rewiring the alternator output wire to the passenger side battery. This information can be found on the Moparman site.

If there are ground problems on your truck, these can cause excessive AC voltage ripples in the charging system. I recommend doing the W-T ground wiring mod before testing the alternator for AC voltage.

- John

I’m intrigued by this suggestion but in MoparMan’s article he writes: Before doing any testing of the alternator for AC noise, make sure to remove any and all wiring modifications. Return the electrical system back to stock. Make sure there is no extra grounds, relocation of ground wires or noise filters installed before testing the alternator.

You are saying to do the ground relocation first. Can you explain your reasoning for that? I will look for the info about the mod on that site. Thanks!

 

[petersonj]

You are saying to do the ground relocation first. Can you explain your reasoning for that? I will look for the info about the mod on that site. Thanks!

You make a good point here. Moparman's recommendation of, "make sure to remove any and all wiring modifications. Return the electrical system back to stock. Make sure there is no extra grounds, relocation of ground wires or noise filters installed before testing the alternator" is a good general recommendation just to get things to a base value.

The W-T ground wiring mod is the new "base value" because William Timothy Burke (W-T) showed us clearly how poorly the OEM ground circuit wiring was designed and installed in the VP44 trucks - long wiring runs and poor splices, as well as the long run of the alternator output wire mixed with other sensitive wiring inside a conduit.

Excellent electrical connections (positive and negative) and good body, frame, engine block, and battery ground wiring and connections are essential to have clean DC current. Any connection condition less than excellent can contribute to higher AC voltage in the DC circuit, thus generating problems with sensitive computer circuitry, such as generating unwanted signals from sensors that could result in unwanted commands caused by this electrical interference. A hunting command for converter lock-up would be a good example.

There will always be some AC voltage present, but it should be very low. Having the electrical wiring and connections in their best possible condition will result in the lowest AC voltage present. Many people have condemned an alternator for high AC voltage readings only to find out later that the cause was poor wiring grounds.

- John

 

[Reluctant Mechanic]

You make a good point here. Moparman's recommendation of, "make sure to remove any and all wiring modifications….

There will always be some AC voltage present, but it should be very low. Having the electrical wiring and connections in their best possible condition will result in the lowest AC voltage present. Many people have condemned an alternator for high AC voltage readings only to find out later that the cause was poor wiring grounds.

- John

Thank you for that explanation. Now to figure if I can handle this task. I’m always thinking I can tackle stuff with this truck with my Doubting Thomas husband over my shoulder saying “nope.”

I’m wanting to sell this pickup because we recently acquired a friend’s very well maintained 3rd gen with no gremlins. Not a great selling point having the TC locking/unlocking on a test drive!

Just hoping this isn’t beyond me to accomplish!

 

[Topzide]

It's a pretty simple mod to relocate the alternator wire away from other wires. You're more then capable do to other work that you've preformed. A DWM (Digital Multi-Meter) is your best friend finding and fixing this issue. Many users have done this and solved their issues. Grounds have always caused issue on or trucks along with others! My '01 1500 had ground issues and once repaired, things returned to "normal" for the age of the truck. Jump in with both feet and show your husband that you've got the support of TDR to fall back on!

 

[Reluctant Mechanic]

It's a pretty simple mod to relocate the alternator wire away from other wires. You're more then capable do to other work that you've preformed. A DWM (Digital Multi-Meter) is your best friend finding and fixing this issue. Many users have done this and solved their issues. Grounds have always caused issue on or trucks along with others! My '01 1500 had ground issues and once repaired, things returned to "normal" for the age of the truck. Jump in with both feet and show your husband that you've got the support of TDR to fall back on!

 

[Reluctant Mechanic]

Thank you for the encouragement! I’m slow to respond and get going on things because of work and bad weather!

My learning and execution style best follow the cooking recipe model ie. Ingredient list followed by step 1,2,3 etc. Anyone know if this mod is broken down that way? Where’s the best place to source appropriate wire by the foot and connectors? I’ll sit down and try to plan this out when I have a minute…

Also, ok to leave old wires in place and disconnected while bypassing, or do you have to tease the mess apart? Thanks in advance! I sure wish there was a YT video for this!

 

[Ozymandias]

Amazon is your friend for the wiring parts.
Take marin grade connectors/ends, and a hydraulic crimper for the crimps, do not solder them.
Battery connectors - military grade lead connectors with covers.
Shrink tube glue lined, shrink rate 3:1 - 5:1.

Old wires if dead on both ends can stay.