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Max sustained RPM?

Offcamber

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Offcamber Enthusiast

Offcamber

Posted
Posted

2016 2500 Gas double cab. While towing about 7500lbs sometimes to maintain highway speed (65) the truck will drop down in gear to rev at about 4500RPM. Is this okay to sustain for the duration of the grade. My Dodge would do the same thing and I always felt I was going to see a piston shoot through the hood. I also noticed once the grade eases up it doesn't like to up shift.Takes a while before it will drop the rpms. My 1500 towing the same trailer didn't do this nor did it run as high an RPM as the 2500.

 

Thanks

Bxnanaz Enthusiast

Bxnanaz

Posted
Posted

Shouldn't hurt anything... not as long as you have good oil. The 6.0 is pretty underwhelming. We have some at work and they don't have quite the power of my 17 5.3

Dale L Enthusiast

Dale L

Posted
Posted

How long you are running at high RPM is probably the deciding factor. The 6.0 makes peak power at 5400RPM so 4500 is certainly within the parameters for the engine but the engines aren't intended to run constantly at peak power, or at least not if you want longevity. I'm not afraid to turn an engine up if the need arises but at the same time I try not to thrash my vehicle if it's not needed. If a Kraken is chasing me up the hill then let her wind, otherwise I'll let the speed drop a bit on the grades and let the engine operate where it sounds happy. :)

 

But I'm just some guy on the internet so take my thoughts with a grain of salt.

i82much Enthusiast

i82much

Posted
Posted

The rpm's are not going to hurt it. Just watch your coolant and transmission temps.

This is correct. The engine is designed to hold up under extremely heavy duty cycles, and your computer is programmed to protect your engine. The best way to tow with a gas engine is to (1) buy a truck with a heavy-duty engine with a long track record of reliability under demanding conditions and (2) let it rev all it needs to in order to pull the load you need to pull.

 

You have already accomplished 1. Now you need to relax and do 2.

sdeeter19555 Senior Enthusiast

sdeeter19555

Posted
Posted

When I have pulls like this, mine will sit at 5k for several minutes. The only thing that creeps up at that RPM is engine oil temperature, which I have seen low 240s before (just this past weekend); trans and engine coolant tend to stay put.

 

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Bxnanaz Enthusiast

Bxnanaz

Posted
Posted

When I have pulls like this, mine will sit at 5k for several minutes. The only thing that creeps up at that RPM is engine oil temperature, which I have seen low 240s before (just this past weekend); trans and engine coolant tend to stay put.

 

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Didn't know the newer 2500s had an oil temp display, pretty cool. 240 is still well with oils designed operating temp

sdeeter19555 Senior Enthusiast

sdeeter19555

Posted
Posted

Didn't know the newer 2500s had an oil temp display, pretty cool. 240 is still well with oils designed operating temp

They don't, I have a standalone reader...

 

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avalonandl Enthusiast

avalonandl

Posted
Posted

The engine will hold together just use a good synthetic like Mobil 1 or Pennzoil platinum....

sdeeter19555 Senior Enthusiast

sdeeter19555

Posted
Posted

Curious if you can share how steep the grade is, and how long?

If you're referring to me, I pull Seven Mountains on US 322 going to State College, the main grade is around 4 to 6% (about two miles with curves) and the last half mile or so is 8 to 9% (maybe greater) from what I remember (it's steep and has a 90 degree curve right before that increase which makes you lose momentum). That last half mile is 2nd gear and near redline, and like someone else stated, once the truck makes the decision to drop to 2nd, it stays there until well past the crest of the top; leaving out of the throttle only slows your speed, it will not upshift to 3rd.

 

This grade will bring most tractor trailers to under 20mph...with 3.73s and near to 5000 pounds of camper, I can typically maintain 45 to 55mph even at the top.

 

One other thing to remember is that these trucks are smarter than you think, more than once I've had this one limit throttle and shifts, probably to preserve longevity of the drivetrain. I would guess they would pull back power well before you would ever get in danger of a catastrophic failure.

 

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Offcamber Enthusiast

Offcamber

Posted
  • Author
Posted

I don't know the grade. Its not like Rocky Mountain steep just the hills of VT, NH and ME. Thanks for the responses. Next time I will look at the incline gauge and see what it is.

sdeeter19555 Senior Enthusiast

sdeeter19555

Posted
Posted

I don't know the grade. Its not like Rocky Mountain steep just the hills of VT, NH and ME. Thanks for the responses. Next time I will look at the incline gauge and see what it is.

A lot of times the signs descending a grade will have the percent grade.

 

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i82much Enthusiast

i82much

Posted
Posted

If you're referring to me, I pull Seven Mountains on US 322 going to State College, the main grade is around 4 to 6% (about two miles with curves) and the last half mile or so is 8 to 9% (maybe greater) from what I remember (it's steep and has a 90 degree curve right before that increase which makes you lose momentum). That last half mile is 2nd gear and near redline, and like someone else stated, once the truck makes the decision to drop to 2nd, it stays there until well past the crest of the top; leaving out of the throttle only slows your speed, it will not upshift to 3rd.

 

This grade will bring most tractor trailers to under 20mph...with 3.73s and near to 5000 pounds of camper, I can typically maintain 45 to 55mph even at the top.

 

One other thing to remember is that these trucks are smarter than you think, more than once I've had this one limit throttle and shifts, probably to preserve longevity of the drivetrain. I would guess they would pull back power well before you would ever get in danger of a catastrophic failure.

 

Sent from my SM-T350 using Tapatalk

Thanks. That sounds like plenty of power to me! I am surprised to hear the grades are that steep in PA, I doubt I will see many grades that steep even in northeast WA and north Idaho.

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