I can't drive my truck until I find the cause to repair. Since the event described below I've driven it around town and it starts to do the same thing at slower speeds (under 45 mph) after it's been driven for about 40 minutes or 25-30 miles.
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 or otherwise?

Thanks!

 

I read with interest waiting to see what engine codes you pulled from the truck. Not a mention? It seems you have jumped to it being a transmission issue vs an engine issue. Why is that? Do you have the ability to test for fuel rail pressure and/or lift pump pressure during cold start up and when you have decreased power? Have you changed the fuel filter lately?
Back to morning brew . . .

 

Good morning. No codes. The reason why it was originally thought to be tranny was because I had a shift issue for a while. It did not want to start in 1st gear. It would stick in 2nd or 3rd...manual shifting to N and then 1st and then to D would fix issue. Tranny shop replaced solenoid, governor sensor, and adjusted bands, said bands were maxed out, and said to maybe expect tranny issues in the next few thousand miles. That was 6,000 miles ago.

I will check and replace the fuel filter. It was last done 14,000 miles ago. I think the interval is every 15k.

I have a fuel pressure gauge kit with many fittings but unsure if it's for diesel use. Are diesel pressures higher or usually require special tools to check fuel pressure?

Know of good procedures on here to follow for fuel pressure?

Thanks!

 

If the kit is for the low pressure lift pump, it shouldn't matter between gas/diesel.

I understand you can buy a DRB2 to USB reader and use software to read rail pressure. Some readers will allow the storage of info so you can see the pressure over your drive time. Amazon has all sorts of

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, you just need to find the right one. Sorry, can't help further than that.
Back to morning brew . . .

 

Super. Thanks. Just getting to brew mine now...lol
I'll look that up. If I plan on keeping the truck until the body falls of I should gather handy tools. Thanks again.

 

Let me throw in a wild card. What is the possibility of the APS causing this problem? Simple and relatively cheap to change.