Without having any video or audio of the issue we're all guessing. So I'll throw in my experienced guess, cause its fun to speculate... Having owned a ZF (6HP) with a diesel, and a ZF(8hP) in two cars currently. I suspect what your experiencing is a lack of torque converter lockup (which has been a common complaint on ZF diesel pairings). I suspect your experiencing the torque converter slipping on purpose, to help multiply the torque for take off from low speeds and smooth the shifts without retarding engine output. Of course did RAM just use the original tune or modify it from ZF? This would change when and under what conditions the converter locks. Heck my AS69C on its original tune felt like I ran over a curb when slowing and doing a 4-3 downshift, it was a big bump and sometimes a clunk on a 2-3 upshift. Mostly been fixed with updated reprogramming (that I had to pay for). So my point being on the older 6spd in the HO is ram kinda sucks at trans programming, and there is a good chance its just as crappy now on the ZF.
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2025 Cummins ZF Transmission Issue?
- Thread starter scdo
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Oh, my error. I checked the subject title "2025 ZF Transmission Issue?" at least two to three times prior to posting to verify that it didn't include the name "Cummins" in it. I must have missed that.Just 3 for the diesel. 68RFE, AS69RC, and G56.
Only the hemi got the 66RFE.
dreamalaska
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I thought the 2025/26 Cummins + ZF was called the 4.75 Gen…imo the first number should always be the body generation, followed by any engine/transmission updates…
Any luck finding out info? My 3500 is doing the exact same noise and it never use toOk, I’m going to plan to discuss it with them when I go in, likely in the next month. There might be a software update for the tranny. I’ll report back here… please do the same!
I will say I can avoid it by being gentle on the throttle until in 2nd.
Not on my end… my truck is still doing it but I haven’t been in to see the dealer yet.Any luck finding out info? My 3500 is doing the exact same noise and it never use to
Mine also started doing it and I haul some heavy weight with a 30ft and 40ft trailer, and I’ve noticed when it started happening and started to get concerned the transmission was acting up or slipping already, hopefully it’s something simple, but I myself will be taking the truck to the dealership next week and most likely leaving it there.Not on my end… my truck is still doing it but I haven’t been in to see the dealer yet.
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Let us know what they say. Not sure yet when I’ll be able to take mine in.Mine also started doing it and I haul some heavy weight with a 30ft and 40ft trailer, and I’ve noticed when it started happening and started to get concerned the transmission was acting up or slipping already, hopefully it’s something simple, but I myself will be taking the truck to the dealership next week and most likely leaving it there.
I was able to take my truck in for this. As expected, the dealer couldn't reproduce it at first without a load on the back. They did do a TCM update.
I picked up the trailer yesterday and found that the TCM udpate didn't help at all. I was able to get back down to the dealer with the trailer in tow to help reproduce the issue. I went for a short test drive with the deisel tech. He was able to hear the sound and was a bit puzzled. His opinion is that it sounds more like something vibrating underneath the cab than the actual transmission (though he is far from certain). Either way, he heard the sound and agrees it is not normal.
Next step is they're going to have a Ram representative come down to the dealership and we'll repeat the test drive.
Will keep this thread updated but this is going to move slow due to the logistics.
Anyone else have this issue serviced??
I picked up the trailer yesterday and found that the TCM udpate didn't help at all. I was able to get back down to the dealer with the trailer in tow to help reproduce the issue. I went for a short test drive with the deisel tech. He was able to hear the sound and was a bit puzzled. His opinion is that it sounds more like something vibrating underneath the cab than the actual transmission (though he is far from certain). Either way, he heard the sound and agrees it is not normal.
Next step is they're going to have a Ram representative come down to the dealership and we'll repeat the test drive.
Will keep this thread updated but this is going to move slow due to the logistics.
Anyone else have this issue serviced??
So late response but I finally took it in for this exact reason and took my 40ft trailer empty with the truck and was able to recreate the sound with tow haul on, and their response was since they can’t reproduce it without the trailer and because I’m hauling it’ll be hard for warranty to accept. I’m trying to convince the diesel mechanic from the dealership to take a ride with me to get his opinion.I was able to take my truck in for this. As expected, the dealer couldn't reproduce it at first without a load on the back. They did do a TCM update.
I picked up the trailer yesterday and found that the TCM udpate didn't help at all. I was able to get back down to the dealer with the trailer in tow to help reproduce the issue. I went for a short test drive with the deisel tech. He was able to hear the sound and was a bit puzzled. His opinion is that it sounds more like something vibrating underneath the cab than the actual transmission (though he is far from certain). Either way, he heard the sound and agrees it is not normal.
Next step is they're going to have a Ram representative come down to the dealership and we'll repeat the test drive.
Will keep this thread updated but this is going to move slow due to the logistics.
Anyone else have this issue serviced??
So I was able to take mine in when I was scaling about 22k lbs.So late response but I finally took it in for this exact reason and took my 40ft trailer empty with the truck and was able to recreate the sound with tow haul on, and their response was since they can’t reproduce it without the trailer and because I’m hauling it’ll be hard for warranty to accept. I’m trying to convince the diesel mechanic from the dealership to take a ride with me to get his opinion.
Took tech for a ride he heard it and was puzzled, he thought maybe it was over boosting at shift point.
Got the truck back and as per the engineers “your heavy and accelerating hard, it’s gonna shift hard”
So yea… I guess I’ll let it crater
There was a comment by someone mentioning it might be the torque converting unlocking or locking or something so it creates a smooth shift but makes noise.
At this point I’m not sure, tons of KM while towing and nothing has snapped so yea