8-Speed Slams Into Reverse When Cold, Harsh 1-2 Upshift

[Brake_L8]

Hi all, just picked up a 2016 Ram 1500 Sport. It's CPO, had 41,500 miles when I purchased in late August and now has 43,500 on the odometer. Love the truck but this ZF 8-speed (which is great in literally everything it's bolted to) has been acting weird when fluid is cold.

The first shift from Park to Reverse is hard enough to shake/jolt the truck as it engages. If I go immediately from Park to Drive, it is "normal" with no slamming or abnormal behavior. Park to Drive to Reverse also does not produce anything abnormal.

I also notice the truck flaring the 1-2 upshift when fluid is cold. It does not flare the first upshift but will do it one time after ~5 upshifts and then not do it again. It's a bit of a harsh engagement into 2nd when it does this.

About 500 miles ago, the 1-2 upshift "flare" took so long to find 2nd that the transmission panicked and slammed into 3rd instead, setting the CEL. The code was for "incorrect gear ratio" and the local dealership replaced the valve body as a result.

While the 1-2 upshift flare has improved somewhat, the harsh Reverse engagement is still present. Any ideas on how normal that is, or what the issue could be would be appreciated.

My service advisor told me to keep driving the truck and if the valve body didn't fix things, drive it til something else goes wrong and sets a code. I don't love that approach but it's supposedly what is needed for Mopar to approve replacing parts under warranty.

 

[Gary2]

if its anything like the earlier Dodge truck trans I had read the tranny needs to be in neutral in order to circulate the fluid so I usually start it and go to neutral for a couple seconds before I go to reverse and the whole thing seems smoother even on my 2017 8sp. Thats only after it sets all night , after its been cycled once it seems fine the rest of the day

 

[autumnwalker]

I need mine to idle and warm up for awhile as well or it does the same sort of thing (it's never skipped 2nd though). They are designed to rapidly warm up from cold with a transmission warmer fitted (https://www.ramforum.com/threads/8hp70-transmission-heater-thermal-bypass-valve.106865/)

If you have the trans temp gauge (or the 7" cluster to enable it) - start your truck from cold and watch it as it idles. The trans temp will climb rapidly vs. the engine temp.

 

[Ashton]

Sounds like a software issue possibly, take it back to the dealer where you bought it. There's a couple of others on here that had the same issue you described.

 

[Riccochet]

I need mine to idle and warm up for awhile as well or it does the same sort of thing (it's never skipped 2nd though). They are designed to rapidly warm up from cold with a transmission warmer fitted (https://www.ramforum.com/threads/8hp70-transmission-heater-thermal-bypass-valve.106865/)

If you have the trans temp gauge (or the 7" cluster to enable it) - start your truck from cold and watch it as it idles. The trans temp will climb rapidly vs. the engine temp.

Mine climbs rather slowly compared to the engine coolant and oil temps. It takes my trans a good 10-15 minutes of actual driving before it gets up to 185 degrees.

 

[autumnwalker]

Mine climbs rather slowly compared to the engine coolant and oil temps. It takes my trans a good 10-15 minutes of actual driving before it gets up to 185 degrees.

Interesting. When I hit remote start in cold weather and let the truck idle for a few minutes the trans will come up to temp (on the digital gauge) before the engine temp on the "analog" gauge even moves the needle.

 

[Riccochet]

Interesting. When I hit remote start in cold weather and let the truck idle for a few minutes the trans will come up to temp (on the digital gauge) before the engine temp on the "analog" gauge even moves the needle.

my **** must be broken then

 

[madtrucker2016]

Hi all, just picked up a 2016 Ram 1500 Sport. It's CPO, had 41,500 miles when I purchased in late August and now has 43,500 on the odometer. Love the truck but this ZF 8-speed (which is great in literally everything it's bolted to) has been acting weird when fluid is cold.

The first shift from Park to Reverse is hard enough to shake/jolt the truck as it engages. If I go immediately from Park to Drive, it is "normal" with no slamming or abnormal behavior. Park to Drive to Reverse also does not produce anything abnormal.

I also notice the truck flaring the 1-2 upshift when fluid is cold. It does not flare the first upshift but will do it one time after ~5 upshifts and then not do it again. It's a bit of a harsh engagement into 2nd when it does this.

About 500 miles ago, the 1-2 upshift "flare" took so long to find 2nd that the transmission panicked and slammed into 3rd instead, setting the CEL. The code was for "incorrect gear ratio" and the local dealership replaced the valve body as a result.

While the 1-2 upshift flare has improved somewhat, the harsh Reverse engagement is still present. Any ideas on how normal that is, or what the issue could be would be appreciated.

My service advisor told me to keep driving the truck and if the valve body didn't fix things, drive it til something else goes wrong and sets a code. I don't love that approach but it's supposedly what is needed for Mopar to approve replacing parts under warranty.

sounds like their is air bogged in the line do you have a trans cooler on your truck. When they do a fluid change they don't bleed it and air stays up front in the lines. Ive seen a video from a Ram dealer and they filled the truck . Then drove it for 15 mins ,put back on lift and re-topped it because of the front cooler the lines hold a lot of fluid.

 

[Brake_L8]

Update, I tried the "Park to Neutral, then Reverse" trick mentioned above and that didn't really help much. I have whatever stock cooler they come with, assuming there is one. My Fords all had them from the factory.

I'll have to give my service advisor a ring and see about a TCU software update.

 

[RamCares]

Update, I tried the "Park to Neutral, then Reverse" trick mentioned above and that didn't really help much. I have whatever stock cooler they come with, assuming there is one. My Fords all had them from the factory.

I'll have to give my service advisor a ring and see about a TCU software update.

Hi Brake_L8,

If it would be of interest, we would be more than happy to provide you with an additional layer of support while your truck is in service. Our team is just a PM away.

Mark
RamCares

 

[Brake_L8]

Hi Brake_L8,

If it would be of interest, we would be more than happy to provide you with an additional layer of support while your truck is in service. Our team is just a PM away.

Mark
RamCares

PM sent, thank you.


Sent from my iPhone using Tapatalk

 

[RamCares]

PM sent, thank you.


Sent from my iPhone using Tapatalk

Thank you for doing so, I just had a chance to respond!

Mark
RamCares

 

[Burla]

Hi all, just picked up a 2016 Ram 1500 Sport. It's CPO, had 41,500 miles when I purchased in late August and now has 43,500 on the odometer. Love the truck but this ZF 8-speed (which is great in literally everything it's bolted to) has been acting weird when fluid is cold.

The first shift from Park to Reverse is hard enough to shake/jolt the truck as it engages. If I go immediately from Park to Drive, it is "normal" with no slamming or abnormal behavior. Park to Drive to Reverse also does not produce anything abnormal.

I also notice the truck flaring the 1-2 upshift when fluid is cold. It does not flare the first upshift but will do it one time after ~5 upshifts and then not do it again. It's a bit of a harsh engagement into 2nd when it does this.

About 500 miles ago, the 1-2 upshift "flare" took so long to find 2nd that the transmission panicked and slammed into 3rd instead, setting the CEL. The code was for "incorrect gear ratio" and the local dealership replaced the valve body as a result.

While the 1-2 upshift flare has improved somewhat, the harsh Reverse engagement is still present. Any ideas on how normal that is, or what the issue could be would be appreciated.

My service advisor told me to keep driving the truck and if the valve body didn't fix things, drive it til something else goes wrong and sets a code. I don't love that approach but it's supposedly what is needed for Mopar to approve replacing parts under warranty.

I didnt read this thread and I don't know if it was said, but warm up truck in neutral before taking off. Im not 100 on the xf, but the rfe doesn't spin fluid in park, only neutral. With your mechanically heated fluids, this will warm up your fluid. A couple minutes anyhow, might work. Also tow haul button increases line pressure. Intul fca figures out something, these are things to try.

 

[Brake_L8]

I didnt read this thread and I don't know if it was said, but warm up truck in neutral before taking off. Im not 100 on the xf, but the rfe doesn't spin fluid in park, only neutral. With your mechanically heated fluids, this will warm up your fluid. A couple minutes anyhow, might work. Also tow haul button increases line pressure. Intul fca figures out something, these are things to try.

Sitting in Neutral for a few minutes doesn't help at all. Have not tried Tow/Haul but cold operation does seem much better behaved when I am towing, and I engage it immediately after starting the truck and it still sitting in Park, so that theory could test out.

Regardless, it's not normal for any automatic to do what mine is doing when cold. @RamCares has been helpful via PM so hopefully I can get it back to a dealership that can diagnose and move forward.

 

[Burla]

I drove in tow haul 24/7 for 6 years, I just like the way it shifts and like the better fluid flow. Perhaps the only downside might be I need to shore up the valve body gasket, but I am glad to have the tow haul button even when I am not towing.

 

[autumnwalker]

Regardless, it's not normal for any automatic to do what mine is doing when cold. @RamCares has been helpful via PM so hopefully I can get it back to a dealership that can diagnose and move forward.

Are you able to post any of this publicly? My dealer claims there is nothing wrong with my truck, but it exhibits similar problems as you are describing (slamming gears, flaring). The fact that @RamCares thinks it is an issue might help.

 

[Brake_L8]

Are you able to post any of this publicly? My dealer claims there is nothing wrong with my truck, but it exhibits similar problems as you are describing (slamming gears, flaring). The fact that @RamCares thinks it is an issue might help.

It's just been a few PMs documenting my experience so far. I would recommend reaching out to them directly with your concerns as they've been great.

Update on my truck: I dropped it off on Sunday night at the second dealership (not the one who replaced the valve body). The service advisor called last night and said they are going to install a new transmission entirely. Sounds like I just got one made on a Friday at 5 PM as the ZF8 is considered very reliable overall.

 

[chrisbh17]

It's just been a few PMs documenting my experience so far. I would recommend reaching out to them directly with your concerns as they've been great.

Update on my truck: I dropped it off on Sunday night at the second dealership (not the one who replaced the valve body). The service advisor called last night and said they are going to install a new transmission entirely. Sounds like I just got one made on a Friday at 5 PM as the ZF8 is considered very reliable overall.

Keep an eye on it once it is finished.

I have a (bad) feeling that you will experience the same issues down the road. I am still pretty convinced its a software issue and the whole "replacement" thing "fixes" the issue temporarily, until the software goes back to its old ways and you start to feel the bump again.

 

[Brake_L8]

Keep an eye on it once it is finished.

I have a (bad) feeling that you will experience the same issues down the road. I am still pretty convinced its a software issue and the whole "replacement" thing "fixes" the issue temporarily, until the software goes back to its old ways and you start to feel the bump again.

Yeah, I am curious about software as well. Guess we'll see how it goes. If the new trans lasts for another 44k miles, the truck will have 88k on it and can get another one installed before that CPO 100k mile warranty expires.

 

[chrisbh17]

I honestly dont think its very (if at all) harmful to the transmission.

I know the harsh 1-2 upshift is actually programmed in....you can see how much slip is allowed by the TCM and for that first 1-2 upshift of the day it allows about 100 RPM of slip....any other shift (including the 1-2 after the initial one) is only allowed half that or maybe less.

And the bump when stopping...I have it, too. Ive noticed that if I let off the brakes just before the 2-1 downshift, then get back on the brakes, the bump is no longer felt. Ive learned to time it pretty well and either it tuned the bump out of the adaptation values or its just not there enough for me to feel anymore.