High rpm

[fordram guy]

Got a question for yall. I just got this ram 2500 6.42500 6.4 hemi. I am pulling my horse with living quarters bout 14k. When i am in tow haul mode my rpms shoot up to 5k at times, anyone have any trouble like this or something close to it.

 

[drittal]

Sounds normal for hauling that much weight. Gas motors need to rev.

 

[QwikKota]

As long as it's only happening during passing maneuvers or getting up to speed quickly that is fine. If you need 5k to get the wheels moving, you are too heavy.

 

[fordram guy]

That is why i am asking. I am not in any passing or anythunh likw that. It happens when i let off the pedal not when i am on it. As for to much wieght good lord i hope not cause then that means i need a new truck

 

[QwikKota]

It should only get that high on a huge hill or going down a mountain pass if you're not on the throttle. Seems a little odd.

 

[fordram guy]

Ok normal. It still doesn't make sense to me that i let off the pedal and the truck goes from a lower rpm to such a higher one. I mean i can be say 3 and let off it goes straight to 5 and no shifting is going on. But thank anyway

 

[fordram guy]

Going up i haven't had it get that high yet but nothing says i haven't found that big of a hill yet. As for going down why would it do it? I mean i am off the pedal and the truck doesn't shift it lile it goes straight to neutral. I have hit the pedal to get it to shift and it takes it awhile for it to come around

 

[Ratket]

the cruise control is trying to hold the speed by using the motor to slow the truck down.

 

[Ratket]

at 5k rpms.. what gear are you in? or how fast are you going. maybe use the brakes and slow the truck down so the rpms are around 3k or 4k. try to get the truck to go down the hill at 55mph. Best solution, go buy a diesel with a exhaust brake

 

[fordram guy]

Well as for gear i am 5 maybe 6th. I don't use cruise conteol when towing. My speed is around 65 - 70 and as for hitting brakes well i did thinking it would help it drop faster did not work at all. As for the diesl thing thinking very much on going that way for sure now

 

[drittal]

At first I just thought you were not used to a gas motor revving to pull. But the spike from 3k up to 5k when letting off the accelerator is odd. A lot is lost in the translation from what you are experiencing to writing it down in this thread.

I'd say try to get a video of what is going on and show it to the service dept at your dealer or actually take it there with your 14k trailer and reproduce it for them.

 

[tjfdesmo]

I don't have my manual handy, but there was something in there about the function of the +/- button. One way it would limit top gear, but there was a way to make it give max RPM under decel to maximize engine braking. Maybe you are inadvertently activating that somehow? Just going from memory, and that is shaky at best LOL.

 

[Ratket]

5k rpm in 5th or 6th gear is a hell of a lot faster than 70mph .. to be at 5k rpm with those speeds u are in 2nd or 3rd.

 

[fordram guy]

Ok guys i have been told that the cause to this is because its low on fluid. They told me it was thrre quarts low. So does anyone think or have anyway of knowing if that could be a cause. I am lost at this point

 

[fordram guy]

Well at 5k rpm it only at 70mph and going down. Its like the truck is in neutral. Is the best way for me to explain it. No down shifting no nothing just 2k roughly to letting off and it shot straight to 5k. Very strange

 

[cc rider]

Hey Fordram guy. Glad I saw your post. I'm getting this too. I had my toy hauler out last week. I was getting this too. But it was ONLY when going up some hills. And they were some pretty big hills. It was freaking me out cause it was acting like I was flooring it. My th was probably around 13k. I haven't weighed it yet. Who told u it might be low on fluid and what kind of fluid? My tranny temp never went above 170 and it was in the 80s out. On the flats it never does it.

 

[SouthTexan]

Well at 5k rpm it only at 70mph and going down. Its like the truck is in neutral. Is the best way for me to explain it. No down shifting no nothing just 2k roughly to letting off and it shot straight to 5k. Very strange

Assuming that your truck is 4wd with the factory 33s, you would be at around 4,900 rpm in second gear if you have a 3.73 axle ratio or around 5,400 rpm if you have a 4.10 axle ratio. That is also assuming your torque converter was locked in. If you were in tow/haul mode and had the cruise control set to from 65-70 mph then the truck will automatically downshift to use engine braking to keep you at that speed.

There is also something else that happens my 6.7L when I set the tow/haul mode and I have the exhaust brake in auto mode or "smart mode" as it is sometimes referred to. Even with me not having the cruise control set to a certain speed, my truck will detect what speed I let off the accelerator and the exhaust brake will kick in and out at different rates to try and maintain that speed. For instance, if I was starting to go down a hill and I let off the accelerator at 60 mph. The truck will detect that and it will automatically kick on the exhaust brake as needed from partial braking or full braking along with engine braking in order to keep me at 60 mph as I go down the hill. I hardly every have to hit the brakes when this is on. In fact I can't remember the last time I actually used the brakes to slow my speed when going down a hill with the exhaust brake in auto mode.

Maybe this is what is happening to yours. It detects when you are lifting your foot off the pedal going down the hill, and it uses the engine braking to try and maintain that speed. It would not be that uncommon for a gasser to get to 5,000 rpm to slow the truck down using engine braking or "grade braking" as GM apparently calls it in this video.

 

[SouthTexan]

Hey Fordram guy. Glad I saw your post. I'm getting this too. I had my toy hauler out last week. I was getting this too. But it was ONLY when going up some hills. And they were some pretty big hills. It was freaking me out cause it was acting like I was flooring it. My th was probably around 13k. I haven't weighed it yet. Who told u it might be low on fluid and what kind of fluid? My tranny temp never went above 170 and it was in the 80s out. On the flats it never does it.

I think yours is a different issue....

 

[cc rider]

He said he doesnt use cruise control when towing. And now I see that his problem is going down hill after rereading it. I didnt notice mine doing that when going down (just the opposite , when going up it did it). I noticed an "exhaust brake like effect". But my rpms never shot up when going downhill

 

[SouthTexan]

He said he doesnt use cruise control when towing. And now I see that his problem is going down hill after rereading it. I didnt notice mine doing that when going down (just the opposite , when going up it did it). I noticed an "exhaust brake like effect". But my rpms never shot up when going downhill

I know, which is why I said "if" in that sentence and why I said what I said after that.

As far as your issue of going up hills. Is it only when towing up hills and does the engine rev out to 5,000 rpm while the truck is slowing down or maintaining speed while the pedal is to the floor?