Fordzilla

Yeah it was just the conspiracy theorist in me coming to the surface...I'll be OK after a cold shower......Ben

Cam Moore

My truck is a 98.5... bought it a few years ago due to low mileage and the fact it has never been messed with. It's been running great until last week when it started the all too common shift hunting routine.
read all the forum's and how to's and grounding seem to come up a lot. So I got out my trusty digital ohm meter and started poking around.
To my surprise, the first thing I checked: neg battery post to body ground I was getting 1 ohm! Should have been getting 0 ohms! Same for both batteries! Funny though, neg battery post to engine block was reading 0 ohms! A real head scratcher! To make a long story short, I put a temporary bond from the negitive battery post to the body to reduce resistance and surprise surprise, tranny started shifting normally again!
After further testing, I was able to determine that the grounding lead on both batteries were beginning to fail and the wires themselves were the culprits!. I'm thinking the crimp connectors are failing? Haven't had time to fully investigate yet and am still driving on the temp bond until I have time to construct a permanent solution.
Lesson learned? Ohm reading from negative batt post on either battery to any metallic part of the truck should be close to zero. Anything other than that could be causing voltage differentials that could be messing with your ECM.
Hard to believe it's that sensitive, but it seems it is in my case!

Fordzilla

Poor grounds can be a cause of many oddball problems, and easily solved with redundant grounds as well as new battery cables occasionally...I'm glad you fixed yours successfully...Welcome to DTR......Ben

Ylekyote

I know this OP is old but this forum hit keeps showing up in searches so people must still be reading it.

Maybe you know the answer to this unique issue I have on my 2005 Dodge Ram 5.9 Cummins automatic w/overdrive transmission? 196,000 miles.

It's the original transmission and motor. All fluids/oils and filters regularly changed and kept clean/new. Not used to tow often...4-5 times a year at most and 8,000 lb loads at most.

I've asked 4 tranny shops and a few forums, YouTube and Facebook groups but no luck finding same problem or proper fix. I'm wondering if I'm just that special?!?? Lol

One mild Fall day last year I had driven 260 miles on interstate at about 75-80 mph. It began slowly reducing speed over 6 miles from 80 to 15mph. Moving fuel pedal would not do anything but make it stumble a little a couple dozen RPMs up or down. Stopping and restarting it immediately did not help nor did changing gears manually.

All fluids were fine, not too hot and no burning of anything fluid or conduit wire was observed. All looked good under and above it.

I stopped it for 30 minutes as I checked it over. It would drive normally after that, but it would only go 25-30 miles before it would slowly slow down again as described above. I did this over many cycles all the way home 260 miles. I'd turn it off and on again, completely off as it rested for 25 minutes. The batteries seemed to be getting charged (started well each time) and no warning lights were on. Once or twice, when I drove it until it would not even crawl anymore (1-2 mph, I was testing it), it stalled. So it wasn't hard starting or hard-stalling unless I took it all the way down to 1-2 mph speed. It was not idling weird either.

Could this be an electrical ground failure or electronic issue? If I had a battery connection loose or anything disrupting the flow could it cause this? It seems like something is getting tired and needing to cool down or something but nothing was overly hot or smoking. What's weird to me is it's not slipping in the usual way of revving up but not moving. It would usually get no lower than idle.

Tranny shops haven't heard of this before. No transmission codes either. They want to charge me $3,000+ for new or rebuilt tranny. I want to rule out wiring and electronics (that don't throw codes) first.

Any suggestions? Heard of this ever before for an automatic transmission?

Thanks!

AlpineRAM

This does sound like an engine problem to me, because if the transmission had a problem transferring power your engine would rev up and you'd go nowhere.
So, either the ECM or some sensor or wiring on the engine, checking the ECM for codes would be my first step.