2015 2500 6.4 towing/trans experience

[reek]

ok, so this horse has been beat to death. the transmission is less than ideal. I've had such a miserable towing experience this week, I gotta ask. Is there an easy way to check for an update for the transmission factory programming? will the dealer let me know if there's an update?

This week, we took the 9000 lb travel trailer from Sacramento to Santa Barbara. Was in tow/haul mode the whole time. So, going over the mountains going UPHILL, the truck held onto 4th gear forever and wouldn't shift into 5th unless I actually slowed down from 55 to 50 or less. then I would have to very slowly build up speed again just so it wouldn't shift back into 4th. Ok, maybe not a big deal.

The bigger issue was going down hill. I assume these trucks have an incline sensor. down even a mild grade, touching the brakes immediately sends the transmission from 5th to 3rd at 55-60 mph. even with gentle roll on throttle, it won't shift out of 3rd. Add to this, if you even tap the brakes a second time, it shifts into 2nd, holds it until you hit a flat/level area. This means you are near redline, engine screaming, the entire way down the hill (6-10 miles long in this case). I tried switching out of tow/haul. nothing. I just had to slow way down and ride out the hill in 2nd until I hit bottom.

is this considered normal? anyone know of an update/flash?

 

[init6]

Not what I wanted to hear. Getting ready to throw a sour 14k behind mine for a trip through the mountains on the east side of the country.

Did you try using manual shift?

 

[[email protected]]

Can u shift it manually?

2017 2500 MC 6.4L Hemi

 

[BlkZrx]

Normal, guess you should have bought a diesel if you want low rpm mountain pulling..

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[MN-Ram]

It seems like every time I bring my truck into the dealership, which is not very often, they do some sort of flash the vehicle. I know I did have one tranny flash last summer, but I don't know what it was for.

 

[WaterBoy1]

^Same. Had my truck in for an oil change last fall, apparently did a flash for the transmission at the same time.

I don't tow much with mine, but it made a difference in the "lurching" it used to do on slight uphill grades. Don't have that problem any more.

 

[Andrew09HEMI]

Personally I wouldn't think the engine breaking is a bad thing when towing. Guess I'm different but if it was redlining and causing no issues, both uphill and downhill, what's the problem? You'd rather it lug around I guess? Not trying to sound like a **** just saying that's pretty normal and far better than some of the other issues I've heard people having when towing

 

[spoon059]

Can u shift it manually?

2017 2500 MC 6.4L Hemi

My suggestion exactly. The trans tuning in these 6.4's isn't all that great. My buddy has a 2015 with the 6.4 and we tow in the mountains of PA quite often. The trans will try to hold 4th gear, then slam into 2nd... completely skipping over 3rd gear. He found that the best way to handle it was to manually shift the gears and put it in 3rd gear himself when approaching steeper grades. The truck revs, but handles it just fine and pulls his 5er just fine.

I believe the downhill shifting is because of tow/haul. It is trying to use the transmission to hold the trailer back and scrub speed, rather than forcing you to use the service brakes. It isn't burning fuel when it does that, so there isn't really any harm to the engine. If you just don't like how it feels, you can turn off the tow/haul feature and it won't try to scrub speed for you. I believe that you can't turn off that feature while it is being used though. In other words, if the computer has already downshifted and using engine compression to slow you down, it won't "turn off" that feature until the computer decides you don't need that compressive braking anymore. Once your speed was controlled and you were accelerating or maintaining speed again, it wouldn't come back on if you started to go downhill and pick up speed again.

I'm not sure why they designed the trans to act this way... The truck is great outside of this little quirk. You can work around the issue, but it is annoying to have to do.

 

[SHOOT2KILL]

My suggestion exactly. The trans tuning in these 6.4's isn't all that great. My buddy has a 2015 with the 6.4 and we tow in the mountains of PA quite often. The trans will try to hold 4th gear, then slam into 2nd... completely skipping over 3rd gear. He found that the best way to handle it was to manually shift the gears and put it in 3rd gear himself when approaching steeper grades. The truck revs, but handles it just fine and pulls his 5er just fine.

I believe the downhill shifting is because of tow/haul. It is trying to use the transmission to hold the trailer back and scrub speed, rather than forcing you to use the service brakes. It isn't burning fuel when it does that, so there isn't really any harm to the engine. If you just don't like how it feels, you can turn off the tow/haul feature and it won't try to scrub speed for you. I believe that you can't turn off that feature while it is being used though. In other words, if the computer has already downshifted and using engine compression to slow you down, it won't "turn off" that feature until the computer decides you don't need that compressive braking anymore. Once your speed was controlled and you were accelerating or maintaining speed again, it wouldn't come back on if you started to go downhill and pick up speed again.

I'm not sure why they designed the trans to act this way... The truck is great outside of this little quirk. You can work around the issue, but it is annoying to have to do.

Just a little QUIRK...LOOOOOOOOOOOOOOOOOOOOL...

 

[Iron Outlaw]

**** mines down shifted and held a lower gear slowing me down while not in tow haul. A few times without a trailer. If I was hauling a big travel trailer over mountains I would have to bite the bullet and get a Cummins. My gasser is perfect for what I bought it for but it is what it is in the end.

 

[SHOOT2KILL]

ok, so this horse has been beat to death. the transmission is less than ideal. I've had such a miserable towing experience this week, I gotta ask. Is there an easy way to check for an update for the transmission factory programming? will the dealer let me know if there's an update?

This week, we took the 9000 lb travel trailer from Sacramento to Santa Barbara. Was in tow/haul mode the whole time. So, going over the mountains going UPHILL, the truck held onto 4th gear forever and wouldn't shift into 5th unless I actually slowed down from 55 to 50 or less. then I would have to very slowly build up speed again just so it wouldn't shift back into 4th. Ok, maybe not a big deal.

The bigger issue was going down hill. I assume these trucks have an incline sensor. down even a mild grade, touching the brakes immediately sends the transmission from 5th to 3rd at 55-60 mph. even with gentle roll on throttle, it won't shift out of 3rd. Add to this, if you even tap the brakes a second time, it shifts into 2nd, holds it until you hit a flat/level area. This means you are near redline, engine screaming, the entire way down the hill (6-10 miles long in this case). I tried switching out of tow/haul. nothing. I just had to slow way down and ride out the hill in 2nd until I hit bottom.

is this considered normal? anyone know of an update/flash?

According to "Spoonfull" this is just a little QUIRK...Engine @ 6000+ rpm with no way to correct it...I feel your pain...BUT...As mentioned previously your better off in a diesel...

This is a good example of people buying into all 3 big players ******** tow capacity numbers...Just because the manufacturer says the towing capacity is 1,000,000 pounds doesnt mean it can do it in ALL CONDITIONS...Sure the CTD can tow 31k+ according to FCA...BUT...Do you really want to tow that much @ highway speeds in the winter on snow covered roads...

 

[Iron Outlaw]

According to "Spoonfull" this is just a little QUIRK...Engine @ 6000+ rpm with no way to correct it...I feel your pain...BUT...As mentioned previously your better off in a diesel...

This is a good example of people buying into all 3 big players ******** tow capacity numbers...Just because the manufacturer says the towing capacity is 1,000,000 pounds doesnt mean it can do it in ALL CONDITIONS...Sure the CTD can tow 19k+ according to FCA...BUT...Do you really want to tow that much @ highway speeds in the winter on snow covered roads...

Yep just like my 2013 f150 was rated for well over 10000 but when actually towing that it wasnt confident at all.

 

[MN-Ram]

According to "Spoonfull" this is just a little QUIRK...Engine @ 6000+ rpm with no way to correct it...I feel your pain...BUT...As mentioned previously your better off in a diesel...

This is a good example of people buying into all 3 big players ******** tow capacity numbers...Just because the manufacturer says the towing capacity is 1,000,000 pounds doesnt mean it can do it in ALL CONDITIONS...Sure the CTD can tow 19k+ according to FCA...BUT...Do you really want to tow that much @ highway speeds in the winter on snow covered roads...

It's not just FCA claiming these numbers. It's also SAE J2807 testing. Do they test every possible parameter? I think not. But under normal conditions, you should be able to expect the J2807 capacities.

I guess you could say a Ferrari is capable of speeds around 200 mph, but would you want to go that fast on snow covered roads, or gravel roads.

If you want to push 2' of wet snow, get a professional grade plow truck, not a light duty truck. Or better yet, get a front end loader with a push box. I'm not as "old" as you, but I've done my own plowing, and worked with the County plow guys well enough to know that there is much better equipment than any light duty truck.

 

[drittal]

Reek, that is normal.

Everything you describe.

It's in the programming. You evidently had enough of a load that holding 5th was lugging the engine. It would shift into 5th when you let off the accelerator and the programming deemed you no longer needed to be in 4th.

Coming down the hill it is programmed to use engine braking to to help control your speed.

My F150 ecoboost would downshift empty to hold speed down hill. I had it go into 3rd from 6th once in the black hills.

Semis slow way down at the top of passes and use lower gears on the way down to hold speed without relying too much on brakes. Brakes get hit, lose effectiveness and they they are run away. I'm sure you've seen the run away truck ramps and signs at the top instructing trucks to use lower gears.


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[mtofell]

Everything OP describes is the same and normal with my truck.

A few things to keep in mind - this truck has no "redline". It's computer controlled to prevent it (or you) from causing damage.

Manually shifting fixed 80% of the problems you describe - at least that's my experience. The holding 4th and slamming into 2nd is super annoying I agree but completely goes away by just clicking down to 3rd manually. Even with my diesel I'd manually shift for a smoother experience. I have eyes for the road ahead, the tranny doesn't. I just don't expect an auto to be perfect when towing.

The auto-downshift thing when braking can be annoying but hardly ever kicks in for me because I hardly ever use my brakes when out on the highway. If you approach a hill at the right speed and get the right gear locked in it will just hold a nice RPM and hold your speed as you go down. And I'm towing an 11,000# 5th wheel some plenty steep mountains.

Sure, a diesel would probably do some of this stuff better but it's not like this truck is incapable. Overall, I'd agree with spoon059 that these are "minor" annoyances. I guess it just depends on someone's expectations and willingness to work with the truck a bit.

 

[HvyDuty]

I tow an 8000 lbs 30 ft travel trailer that is 11' 8" tall. I used to tow it with a 2015 Ram 1500 5.7L w/ ZF 8spd.

I have to say the 66RFE transmission in the 2500 is the achilles heel of an otherwise great truck, especially when towing heavy and compared to the 8 spd. Unloaded or light towing I have no issues.

I knew this going in to my purchase and for me, the next level beefiness of the 2500 outweighed the transmission. It handles my TT night and day difference vs 1500. I no longer worry about speeding Semi truck passing me. Very relaxed towing experience.

When not in Tow/Haul mode, the only time my truck has downshifted going down a steep incline is when I have the cruise control set. Without the cruise it will just increase speed until I hit the brakes or bottom of the hill.

When towing, I just turn on tow/haul, set the cruise control based on traffic conditions/speed limits and let the truck do its thing.

 

[RLM5150]

I guess I don't understand the problem with 4th gear at 55mph when towing. It's not like it's running hi revs at that speed in 4th gear.

The downhill performance OP described seems odd. I haven't noticed that behavior when towing.

Dealer has flashed mine a couple of times. One of those times corrected an issues where tow/haul mode would bypass 3rd on downshift and go straight from 4th to 2nd. Now it will use 3rd gear on downshift in Tow/Haul mode.

I don't know how we can check if a newer flash is available. I would take it to the dealer and have them check.

 

[reek]

thanks all for the input. as originally stated, the up hill in 4th gear wasn't really my issue, just an observation different than every other truck I've ever owned and buying a diesel to avoid this a few times a year isn't realistic.

the down hill engine braking with ever increasing RPMs in 2nd gear was my real issue/question. It engine braked just fine in 3rd with moderate RPMs and I really didn't need much or any brakes but if a car pulls in front of you and you touch the brakes, it goes into screaming 2nd gear mode. Didn't realize these motors didn't have a "redline" (good to know) but the gradually climbing RPMs to 6000 had me concerned.

...if it was redlining and causing no issues, both uphill and downhill, what's the problem? You'd rather it lug around I guess?

not sure how I'd lug a motor going down hill but I do agree, redlining rarely causes issues. my concern was the damage that over revving could do, the exponential increase in stress /wear, etc. but I guess that's a non-issue now - thanks for the info mtofell.

 

[Andrew09HEMI]

Remember the 6.4 is designed for the extra strain, heat from towing in all situations. Extra cooling jets in the block, coated valves forged rods are all there to avoid excessive wear in these situations. Didn't mean to come across like a **** in my post either!

 

[spoon059]

According to "Spoonfull" this is just a little QUIRK...Engine @ 6000+ rpm with no way to correct it...I feel your pain...BUT...As mentioned previously your better off in a diesel...

Very easy way to correct it... manually shift into 3rd. Attention to detail.