Just got back from taking our new toy hauler and '16 Ram 3500 SRW 6.7 68RFE camping for the first time. An 800 mile roundtrip to the Colorado River that included a number of steep grades and 107-115 degree daytime temps---obvious fallout from this SW US heat wave that's been on the news. The toy hauler with toys and gear onboard weighed ~12,750 lbs. with a pin weight of ~2,650 lbs.
This is our first diesel. Previous rig was a Tundra 5.7 that we used to pull a 7,000 lb. toy hauler (loaded).
This trip really drove home the diesel experience: 1) The Cummins simply pulled like a beast. Steady. Confidently. 2) The automatic exhaust brake was the cat's meow! Its operation coming down 6-7 percent grades and during normal braking on the flats was simply phenomenal. Hearing it in operation was icing on the cake. And last, but not least 3) MPG's. We maintained 55-60 mph for most of the drive--doing what we could to reduce stress on the toy hauler's China bombs in 107-115 degree heat. Overall MPG at these speeds, hand calculated, was 11.1 MPG (EVIC displayed 12.0). Considering the tow weight (almost 13k) and the constant elevation changes---11.1 MPG was a pleasant surprise to say the least. The same drive got us 8.5 MPG with the Tundra.
The only concern we had on the entire trip was a short, 4-5 mile climb (on a secondary road) that resulted in a spike in tranny temps. Speed was limited to 25-30 mph (due to switchbacks) on grades that I would estimate to have been around 7-10 percent. Turbo boost hovered around 15-20 PSI for most of the climb. It didn't take long for the radiator fan to activate--hard not to notice---it's loud. In any case, tranny temps (while staying in the same gear for the entire climb) spiked to 195-198 degrees (flat towing it's typically 168-172).
All in all an awesome first camping trip with our new rig.
This is our first diesel. Previous rig was a Tundra 5.7 that we used to pull a 7,000 lb. toy hauler (loaded).
This trip really drove home the diesel experience: 1) The Cummins simply pulled like a beast. Steady. Confidently. 2) The automatic exhaust brake was the cat's meow! Its operation coming down 6-7 percent grades and during normal braking on the flats was simply phenomenal. Hearing it in operation was icing on the cake. And last, but not least 3) MPG's. We maintained 55-60 mph for most of the drive--doing what we could to reduce stress on the toy hauler's China bombs in 107-115 degree heat. Overall MPG at these speeds, hand calculated, was 11.1 MPG (EVIC displayed 12.0). Considering the tow weight (almost 13k) and the constant elevation changes---11.1 MPG was a pleasant surprise to say the least. The same drive got us 8.5 MPG with the Tundra.
The only concern we had on the entire trip was a short, 4-5 mile climb (on a secondary road) that resulted in a spike in tranny temps. Speed was limited to 25-30 mph (due to switchbacks) on grades that I would estimate to have been around 7-10 percent. Turbo boost hovered around 15-20 PSI for most of the climb. It didn't take long for the radiator fan to activate--hard not to notice---it's loud. In any case, tranny temps (while staying in the same gear for the entire climb) spiked to 195-198 degrees (flat towing it's typically 168-172).
All in all an awesome first camping trip with our new rig.
Cummins12V98 wrote:transamz9 wrote:Cummins12V98 wrote:coolbreeze01 wrote:
Downshifting and backing out of the throttle will help your engine/transmission run cooler. No need for high revs but you don't want to lug it either.
Computer will do the job shifting when needed, just hold it to the floor. Aisin trans stays cool in any conditions. Pic is pulling long 7 percent grade west of Golden Colorado, 32,950# per Cat Scales.
Most of us don't need to hold it to the floor to pull our units up grade. With the torque in these trucks I can often pull grades at 15-1700 RPM. If I left the computer do it then that's where it stays. It's easier on the trans to lock it down in 5th and let'er cool.
Sure 5th with 33K combined NOT to the floor, whatever.
I didn't say you don't. I say most of us don't. Don't twist my words. There are a lot of times my truck will pull my 28,000 combined up a grade at 15-1700 RPMs if I let the computer run things. All I was saying is that if the grade is very long I will lock it down a great so it will turn more RPM and keep things cooler.;) You have to keep in mind that me running in 5th is like you running in 6th.
transamz9 wrote:Cummins12V98 wrote:coolbreeze01 wrote:
Downshifting and backing out of the throttle will help your engine/transmission run cooler. No need for high revs but you don't want to lug it either.
Computer will do the job shifting when needed, just hold it to the floor. Aisin trans stays cool in any conditions. Pic is pulling long 7 percent grade west of Golden Colorado, 32,950# per Cat Scales.
Most of us don't need to hold it to the floor to pull our units up grade. With the torque in these trucks I can often pull grades at 15-1700 RPM. If I left the computer do it then that's where it stays. It's easier on the trans to lock it down in 5th and let'er cool.
Sure 5th with 33K combined NOT to the floor, whatever.
fireman41 wrote:transamz9 wrote:Cummins12V98 wrote:coolbreeze01 wrote:
Downshifting and backing out of the throttle will help your engine/transmission run cooler. No need for high revs but you don't want to lug it either.
Computer will do the job shifting when needed, just hold it to the floor. Aisin trans stays cool in any conditions. Pic is pulling long 7 percent grade west of Golden Colorado, 32,950# per Cat Scales.
Most of us don't need to hold it to the floor to pull our units up grade. With the torque in these trucks I can often pull grades at 15-1700 RPM. If I left the computer do it then that's where it stays. It's easier on the trans to lock it down in 5th and let'er cool.
You know those big horse power and torque numbers are made and wide open throttle.
You don't have to be WOT to get full torque output. 3/4 throttle under a hard pull will give full boost. The last 1/4 is to tell the truck it needs to gear down for mor torque.
transamz9 wrote:Cummins12V98 wrote:coolbreeze01 wrote:
Downshifting and backing out of the throttle will help your engine/transmission run cooler. No need for high revs but you don't want to lug it either.
Computer will do the job shifting when needed, just hold it to the floor. Aisin trans stays cool in any conditions. Pic is pulling long 7 percent grade west of Golden Colorado, 32,950# per Cat Scales.
Most of us don't need to hold it to the floor to pull our units up grade. With the torque in these trucks I can often pull grades at 15-1700 RPM. If I left the computer do it then that's where it stays. It's easier on the trans to lock it down in 5th and let'er cool.
You know those big horse power and torque numbers are made and wide open throttle.
Cummins12V98 wrote:coolbreeze01 wrote:
Downshifting and backing out of the throttle will help your engine/transmission run cooler. No need for high revs but you don't want to lug it either.
Computer will do the job shifting when needed, just hold it to the floor. Aisin trans stays cool in any conditions. Pic is pulling long 7 percent grade west of Golden Colorado, 32,950# per Cat Scales.
Most of us don't need to hold it to the floor to pull our units up grade. With the torque in these trucks I can often pull grades at 15-1700 RPM. If I left the computer do it then that's where it stays. It's easier on the trans to lock it down in 5th and let'er cool.
coolbreeze01 wrote:
Downshifting and backing out of the throttle will help your engine/transmission run cooler. No need for high revs but you don't want to lug it either.
Computer will do the job shifting when needed, just hold it to the floor. Aisin trans stays cool in any conditions. Pic is pulling long 7 percent grade west of Golden Colorado, 32,950# per Cat Scales.
