Last week I started to experience lockup converter "flutter". Meaning,,, at low rpm highway speeds (40-60 mph), when needing to gently accelerate or climb a hill the torque converter starts rapidly fluctuating from lockup on/off.
I installed one of those electric noise filters today on the wire coming out of the PCM and that helped, greatly reduced the amount of flutter, but still does it.

Please help as this is my daily driver.

2003: 2500 Cummins 4x4 auto (48re), 292xxx miles, Smarty Touch running the "tow" tune.

I have heard from reliable sources there is wire somewhere underhood that can also be grounded to help with this problem. Can anyone please point me towards a link with a good writeup of which wire to tie to ground?

From what I have read, and a local transmission shop has told me, this is very common on my truck, its electrical "noise" causing the converter to think it is supposed to be switching. I searched this forum but to my surprise did not come up with a thread on this topic (maybe I searched wrong?)

APPS appears to be fine based on the TPS readings from my Smarty Touch.

I change the fluid and filter every 50k miles and adjust bands.

Transmission was rebuilt at 210k when I found a broken piece of snap ring laying in the pan

I really, really need to fix the truck this weekend to use it for work Monday and then a 4 hour drive to TN later this week.

Thanks in advance for any help

--Matt

 

This is probably what you need.

https://us.bddiesel.com/products/dod...ator-1994-2004

You can also try wrapping the wire from the alternator to the battery in aluminum foil, to help isolate it.

 

Thanks for the reply! ,,, but I already installed one of those noise filters. Not the BD-brand name one, but pretty much the same. I said that in my OP but it was a really long post so easy to miss.

Here is the noise filter I installed, a local transmission shop I trust had it in stock: Noise Filter for TPS Signal by ATSG - ATSG Bookstore (ATSG NF-27)

I am still running the factory-original alternator, I was suspecting it was starting to produce "dirty" voltage, but using my Fluke multimeter I am only picking up 0.3 VAC from the positive stud on the alternator to the alternator case with the engine running (headlights on, blower motor on high) .... I was of the understanding anything less than 0.5 VAC was considered clean.

Back in November of last year a local shop installed new batteries. Normally I would do this myself but they were warranty and the new set was free (but the shop had to install them) (Interstate batteries). Then in January in some really cold weather the truck barely turned over at work, so I popped the hood to find the positive cable on the passenger side battery was loose. Snugged it up and went on about my way. No idea how long it was loose (maybe since that shop installed it?) but I know loose connections can play havoc on electrical systems,,, almost wonder if it has made my alternator "noisy" (out of "phase" a bit, or diode going out?) from running with the loose connection.

I am considering a new alternator, hate to just throw parts at it but at least they not expensive (Rock Auto for the win). The serpentine belt is about 8 years old with 80-90k miles anyway so plan to change that too while there (along with a squeak tensioner....)

 

UPDATE: new alternator made no difference.

Disconnected all electrical connectors from transmission, all look good, clean and reinstalled, no difference

****Anyone ever find that a new APPS fixes this?** I can read throttle position% on my Smarty Touch and it seems to move in line with the pedal..... Hate to toss another $200 at it but I really need my truck

Please help if you can. I am starting to get desperate! Jobs are backing up and I need my truck. Been driving local but avoiding long trips.

 

You should check and replace your cables. They are prone to corrosion that goes inside the insulation you can't see. Especially the crossover cable. As you know, the connections and good batteries are super important. If you had a set of bats replaced under warranty then need to suspect why and its probably in the cable system.

 

UPDATE: FIXED! Posting this here in case this can help someone else.

I took the truck to a local transmission shop that I trust, they were very familiar with this problem. After already doing everything I described above, what finally fixed this was a simple fix.

At the PCM wiring harness, center plug, they ran about 1 foot of wire to a ground on the firewall to the "ground wire" that provides system-ground to the internals of the PCM.

I'm not sure if doing this first would have fixed it, but if I had to do this over again that is what I would try first.

I will try to upload some pictures when I can. Also, I don't think they cut that wire completely, just spliced in a ground wire.