What's new
By:

RAM RHO Transmission Issue

itsmekylep said:
I admire the unwavering support you have in the idea that the lifts aren’t causing this, but right now with the examples we have available to us, it’s pretty clear that it is.

Again, not a single person with a 2+ kit can come on here and say their truck is perfect, every launch, every time. Yet we have a handful of guys that can confidently say their truck is not right after the 2+ kit.

I’m not trying to argue by any means and I would love nothing more than to keep this kit and blame the truck, but there just isn’t enough info (yet) to say otherwise. I’m not blaming Foutz or Eibach either.

Now, that’s not to say Ram isn’t “listening”
and can quietly fix the problem with a software patch sometime down the road. Fingers crossed.
Click to expand...
But that doesn’t explain the actual ZF transmission widespread issues without any lifts being reported. I’m telling you these transmissions are having issues. Maybe there is merit in saying lifts perhaps exasperates the known issues, but I’m convinced the lifts aren’t the root cause.
 
frogjbm said:
But that doesn’t explain the actual ZF transmission widespread issues without any lifts being reported. I’m telling you these transmissions are having issues. Maybe there is merit in saying lifts perhaps exasperates the known issues, but I’m convinced the lifts aren’t the root cause.
Click to expand...
I can agree with that logic. Although something that communicates with the transmission via the active dampening sensor is not happy with the extra angle we’ve put on it. Going back to stock seems to make it happy.
 
itsmekylep said:
I can agree with that logic. Although something that communicates with the transmission via the active dampening sensor is not happy with the extra angle we’ve put on it. Going back to stock seems to make it happy.
Click to expand...
Well one cannot wait idly by until these manufacturers get their heads out of their assholes.
 
frogjbm said:
I’m not sold on the lift causing this. I personally think it’s related to transmission module or some sort of module failing.

Until it can be proven the lift removal somehow fixes this scenario, it’s purely hypothetical.

There are known issues with these transmissions across the country, not just RHO specific, and guess what, this exact issue is listed as a known problem. The issue is, most dealers are stupid as fuck and nobody knows how to change a God Damn air filter these days, much less troubleshoot with some degree of intelligence.

Some suggestions below, I’m leaning to either 1, 2, 3.


1. Transmission Control Module (TCM) Calibration or Software Issue

• Symptom: Harsh or delayed shifting, failure to shift at WOT.

• Fix: Check for any software updates or reflashes for the TCM. A dealership can diagnose and update the module if needed.


2. Throttle Position Sensor (TPS) or Accelerator Pedal Sensor

• Symptom: Incorrect readings at WOT can confuse the TCM and delay or prevent shifting.

• Fix: Scan the truck with a diagnostic tool to check for TPS error codes or erratic voltage behavior.


3. Valve Body or Solenoid Issues (ZF 8-Speed Transmission)

• The 2025 Ram RHO uses a version of the ZF 8HP transmission.

• Symptom: Solenoids sticking or valve body faults can prevent proper gear engagement.

• Fix: Requires scan tool diagnostics, possibly a valve body service or replacement.


4. Low or Dirty Transmission Fluid

• Symptom: Overheating or insufficient pressure can delay shifting.

• Fix: Check the fluid level and condition (burnt smell or dark color = bad). Top off or replace fluid as needed.


5. Cold Transmission or Torque Management Strategy

• Newer trucks often have torque management and shift logic to delay shifts under load if the transmission is not at optimal temperature.

• Fix: Let the truck warm up. If it consistently fails to shift even when warm, there may be a deeper issue.


6. Adaptation Learning or Reset Needed

• The transmission adapts to driving behavior. Aggressive driving might cause shift logic to behave oddly if it’s not “learned” correctly.

• Fix: A dealer can perform a reset of adaptive transmission learning.


7. Mechanical Failure or Internal Transmission Damage

• While unlikely on a new 2025 model, internal clutch pack or band failure could cause shift issues.

• Fix: Transmission teardown and inspection—last resort if all else fails.


Known/Reported Issues with the ZF 8HP75 (Newer Models)

1. Delayed or Harsh Shifts

• Symptoms: Harsh 1-2 or 2-3 shifts, especially under load or cold starts.

• Cause: In many cases, this is linked to adaptive learning or TCM software bugs.

• Fix: Dealership TSBs (technical service bulletins) or software updates often resolve this.


2. Shift Refusal at WOT (Wide Open Throttle)

• Symptoms: Transmission stays in first gear or delays the 1-2 shift at WOT.

• Cause: Throttle input misinterpretation or torque management calibration issues.

• Fix: TCM flash update, sometimes accompanied by engine control module (ECM) updates for coordination.


3. Torque Converter Lockup Shudder

• Symptoms: Shudder or vibration at low RPMs or when shifting into higher gears under light throttle.

• Cause: Fluid degradation or software controlling converter clutch lockup too aggressively.

• Fix: Fluid flush with correct ZF Lifeguard 8 fluid, software reflash, or (in rare cases) torque converter replacement.


4. Transmission Overheating Warnings

• Symptoms: Overheating messages or limp mode under moderate towing or hill climbs.

• Cause: Some tuning or sensor calibration issues with thermal management, especially on high-output models.

• Fix: TSBs issued on some models to address temp thresholds and fan logic.


5. Intermittent No-Shift or Stuck in One Gear

• Symptoms: Transmission won’t shift out of a gear or stays in a lower gear.

• Cause: Valve body solenoid issue, or rare internal pressure control problem.

• Fix: Dealer diagnostics needed—some units have had valve body replacements under warranty.
Click to expand...
@frogjbm you use ChatGTP on this one? 😉 Kidding aside, it’s absolutely the lift that’s causing the issue. It’s hanging in gear because it thinks we’re on the dunes in Baja mode. I’m a software implementor by day, I promise you this has zero to do with any physical valving.
 
As noted much earlier I absolutely believe the lift and the failure to adjust for the sensors is most definitely causing these issues. I’m sure changes have been made for drive modes, accident avoidance , self driving etc that the TRX didn’t have.

The basic trans issues have been around since they were first introduced. I’m with @itsmekylep that the lift IS the cause.

My Mazdas, Hondas etc all needed adapters etc when lowering the car to prevent different issues, why wouldn’t the truck when lifting it. Hell, the article I posted shows the sensors right there.

Chris
 
I lifted my 2020 1500 limited with a 4" BDS kit. The kit came with brackets for the ride height sensors to relocate them to the original position after installing the lift so the suspension computer didn't see a change. It was a simple bent sheet metal bracket painted black. The brackets in the picture are from Rough Country, but they are almost identical to the ones that came from BDS. I would think this may be the solution to the RHO lifted/leveled issues. I don't believe these brackets will fit our trucks, but maybe we need someone to make something similar.
 

Attachments

  • ysfpaek-.webp
    ysfpaek-.webp
    23.2 KB · Views: 8
@DaveRho I remember you did all four springs but went with 1.6/1.5 and 37s. Have you had any issues?
 
Elonmsk said:
@frogjbm you use ChatGTP on this one? 😉 Kidding aside, it’s absolutely the lift that’s causing the issue. It’s hanging in gear because it thinks we’re on the dunes in Baja mode. I’m a software implementor by day, I promise you this has zero to do with any physical valving.
Click to expand...
I did lol. 😂

Fine. The relocation brackets are interesting. Link?
 
guys, keep in mind the Rough Country relocation brackets I posted the picture of are not for a TRX/RHO. They were for a 19-24 DT ram 1500 with 4 corner air suspension. Ours trucks ride height sensors are very different from the ones those brackets were made for. Our height sensors have accelerometers attached to them. I just thought the concept of a relocation bracket may be the solution to the problem.
 
This is one of our more interesting and helpful threads here.

I appreciate the input and the troubleshooting from you guys and I hope that Ram does come with a fix, but I'm glad that something was identified, even through the pain of long service visits and frustration
 
TXRHO said:
guys, keep in mind the Rough Country relocation brackets I posted the picture of are not for a TRX/RHO. They were for a 19-24 DT ram 1500 with 4 corner air suspension. Ours trucks ride height sensors are very different from the ones those brackets were made for. Our height sensors have accelerometers attached to them. I just thought the concept of a relocation bracket may be the solution to the problem.
Click to expand...
Ya. I’m going to see if I can find someone to make a genetic bracket, just to test it.
 
cconnorhtx said:
This is one of our more interesting and helpful threads here.

I appreciate the input and the troubleshooting from you guys and I hope that Ram does come with a fix, but I'm glad that something was identified, even through the pain of long service visits and frustration
Click to expand...
It’s crazy that Ram authorized transmission assemblies for some guys. You would think some engineer , somewhere would immediately know and ask the question. I assume just like any other company internal departments have poor communication between each other. Lol
 
itsmekylep said:
It’s crazy that Ram authorized transmission assemblies for some guys. You would think some engineer , somewhere would immediately know and ask the question. I assume just like any other company internal departments have poor communication between each other. Lol
Click to expand...
It is crazy but absolutely not surprising as the technicians now have absolutely ZERO ability (or authorization - likely both) of doing any actual troubleshooting

My truck sat at the dealer for a month with 500 miles on it because THEY installed my Mopar power running board incorrectly which blinked my odometer and made my driver's door lock inoperable. It took them a month to nearly completely rebuild my driver's door (harness, bracket, locking module, and something else I have forgotten).

I had to send an email to the GM and the Service Manager begging them to look at the install of the running boards because my SA would not listen to me.

30 second fix
 
You must log in or register to reply here.

Ram RHO Forum Photos

Featured image Featured image Featured image Featured image Featured image Featured image

Ram RHO Forum Photos

Featured image Featured image Featured image Featured image Featured image

Latest Discussions...

Trending content

Back
Top