68RFE Hard Shift

[jwynnejr1]

My 2018 2500 6.7 is doing what I would call a hard shift from 3 to 4, except for its happening before it shifts to 4. According to the dash, it’s shifting into third gear and about halfway up the gear it feels like it’s hard shifting, but it hasn’t actually shifted into 4 yet. It’s happening around 28-35 mph. Any explanation for this? No check engine or transmission lights and it’s not throwing any codes and dealer says it’s normal, but it just started doing it last week.

 

[U&A]

The first thing I would do is check fluid levels by following the HOT check procedure.

Cold checks are not reliable for transmissions.

Add or remove as necessary. Mine was almost a quart low from the factory.


If it’s good then id unhook the battery cables both negative and positive. touch the CABLES together for a good 10 seconds and let the truck sit with the cable disconnected for about 15 min.

This would be like a reboot to default on your PCM.

This will cause the transmission to relearn you’re driving techniques.

Once I re-connect the battery cables to the terminals, the next time I drove it I would be kinda aggressive but not overly so (just a bit heavy footed) for the next handful of times i drive.

If it still does it and I would take it to the dealer.

JMO.


Sent while firmly grasping my redline lubed RAM [emoji231]

 

[jwynnejr1]

Fluid level is good at operating temperature. I am certainly considering giving your PCM reboot procedure a try. My only concern is the capacitance of the 12v system in the truck. I would think that since there is some stored energy, it would not be a good idea to take the cables off of my batteries and then touch the hot to ground immediately for ten seconds. My thought is that it would short out the system. Would you mind explaining that part a little more to me?

Thanks very much for your help!

 

[U&A]

If you think for some reason it’s not safe with your system then don’t listen to me.

You’re going to have to find out from someone else with a Cummins if that is OK. It is done all the time with a hemi. In fact I think it is a actual procedure that the dealer uses but I do not know for your truck if you’re thinking it’s different.


Sent while firmly grasping my redline lubed RAM [emoji231]

 

[U&A]

Add a minimum just disconnect the negative terminal for a good 15-20minutes. Not sure if that’s going to give you the reboot you’re looking for but I have heard of people doing this


Sent while firmly grasping my redline lubed RAM [emoji231]

 

[jwynnejr1]

I don't think it's any different. 12V ground system is a 12V ground system.

 

[U&A]

Well I’m no mechanic by any means but I did it about 10 times this weekend trying to solve my problem. I was told by some knowledgeable members on here to try it.



Totally up to you if you do it


Sent while firmly grasping my redline lubed RAM [emoji231]

 

[RamCares]

My 2018 2500 6.7 is doing what I would call a hard shift from 3 to 4, except for its happening before it shifts to 4. According to the dash, it’s shifting into third gear and about halfway up the gear it feels like it’s hard shifting, but it hasn’t actually shifted into 4 yet. It’s happening around 28-35 mph. Any explanation for this? No check engine or transmission lights and it’s not throwing any codes and dealer says it’s normal, but it just started doing it last week.

I certainly understand why this would be concerning, jwynnejr1. If you plan to address this with your dealer again or visit a different location for a second opinion, please let us know via private message. We would be more than happy to provide you with an additional layer of support for that process.

Mark
RamCares

 

[mtnrider]

Sounds like the torque converter locking to me based on the gear/speed.

Side note, how are you seeing the current gear on the dash? Is that new for the 2018? Only way I can see it on my 2016 is if I use the manual shift buttons.

.

 

[SouthTexan]

Sounds like the torque converter locking to me based on the gear/speed.

This! It is the torque converter locking half way through third gear.

 

[jwynnejr1]

This! It is the torque converter locking half way through third gear.

Is that normal operation? It hasn't been as pronounced until about a week ago.

 

[jwynnejr1]

Sounds like the torque converter locking to me based on the gear/speed.

Side note, how are you seeing the current gear on the dash? Is that new for the 2018? Only way I can see it on my 2016 is if I use the manual shift buttons.

.

I use the manual shift button from stopped position to select my maximum gear, then the actual gear it's in is on the left side of the maximum gear. I drive through gears 1-3, and then half way through gear 3 I feel the hard shift.

 

[SouthTexan]

Is that normal operation? It hasn't been as pronounced until about a week ago.

Did someone else drive your truck recently? If so, then it could have learned their driving and adjusted shift strategy and firmness to their driving style. Another thing that alters lockup is tow/haul mode and gear selection mode like you stated you do above. Both will increase max line pressure which makes for a firmer shift.

No worries though. it will not mess up your trans or torque converter. Firmer/quicker shifts and engagement(to a point) is better for the trans because there is less slippage and less heat between gear changes. Smoother shift means more slippage, heat, and clutch wear.

Mine is tuned to lock in 4th between 28-40 mph depending on my throttle input. In tow haul mode, it locks in 3rd gear at roughly the same speeds. It is very pronounced and it is almost like another shift in between gears like you are saying.

 

[jwynnejr1]

Did someone else drive your truck recently? If so, then it could have learned their driving and adjusted shift strategy and firmness to their driving style. Another thing that alters lockup is tow/haul mode and gear selection mode like you stated you do above. Both will increase max line pressure which makes for a firmer shift.

No worries though. it will not mess up your trans or torque converter. Firmer/quicker shifts and engagement(to a point) is better for the trans because there is less slippage and less heat between gear changes. Smoother shift means more slippage, heat, and clutch wear.

Mine is tuned to lock in 4th between 28-40 mph depending on my throttle input. In tow haul mode, it locks in 3rd gear at roughly the same speeds. It is very pronounced and it is almost like another shift in between gears like you are saying.

Thanks for this great information. Is there anything I can do to make it stop doing it? Would a relearn or reflash by the dealer help in your opinion?


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[SouthTexan]

Thanks for this great information. Is there anything I can do to make it stop doing it? Would a relearn or reflash by the dealer help in your opinion?


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It will eventually relearn to your driving style after 50 miles or so. You can try not putting it in gear selection mode where you see what gear you are in. This will alter shift points, max line pressure and lock up strategy.


If you are looking to see what gear you are in, then I would recommend an Edge Insight CTS2. It monitors many parameters such as boost, DPF regen, EGR flow, exhaust temps, exhaust back pressure, current gear, torque converter lock up and many more.

 

[jwynnejr1]

It will eventually relearn to your driving style after 50 miles or so. You can try not putting it in gear selection mode where you see what gear you are in. This will alter shift points, max line pressure and lock up strategy.


If you are looking to see what gear you are in, then I would recommend an Edge Insight CTS2. It monitors many parameters such as boost, DPF regen, EGR flow, exhaust temps, exhaust back pressure, current gear, torque converter lock up and many more.

I like the sound of that. To answer a prior question, nobody else has driven my truck. My driving habits change depend on mood, though.


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