What's the best way to pull Hills?

[novelmike]

I've got a 2012 Ram 1500 4x4 with the 5.7 and the 6speed trans.
I'm curious as to what's everyone's opinions (or better yet, facts) are on the best way to pull hills. Long steady grades, towing 7,000+lbs.
Is it best to be able to hold my MPH and have the RPM's around 2500 RPMs or have the RPMs much higher at 4000+?
The higher the RPMs the higher the oil temperature right? How do the RPMs affect transmission temps? I can most likely pull it in 3rd or 2cd gear. While holding a steady speed. But what about dropping down to first gear and my RPMs being at 4800? These motors aren't at their peak torque till over 4000 and horsepower till 5000. Is it silly to pull a hill and keep my RPMs that high for several miles? How will that effect my motor and trans temps?

 

[louie217]

I drive a semi.......
My engines operating range is 1000 to 1500 rpm. 1700 is max. Long steady grades are tricky. You need that turbo working. (Spooled up and boost up.) So inhondown a gear at 1200 and go into the lower hear to get 1700. More air means more turbo spool means more boost.
Your in a gas with no turbo. So in my professional experience, you need to find the specs for where max tq is and keep your rpm there. Tq is pulling power, hp is go fast. So I mean it's up to you. Hold steadybwith more strain will decrease mpg. And make the engine hotter. Oil temp will rise but will cool back off quickly. Id put a larger trans cooler on, possibly a deep sump trans pan. If your worried about engine oil temp you could add a cooler. Or just leave it alone and maintain speed and go down a couple gears. Or buy a diesel.

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[911ems]

I was always a believer in letting the rpms work for the truck. My little garage car spools to 11k rpms so to me 5k in the truck doesn’t bother. I usually lock out the top gear and go. If I feel that the truck is struggling and hasn’t downshifted it’s self yet, then I’ll put it the next lower gear. I haven’t pulled with the 8sp yet but I’ve heard good things.


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[GsRAM]

let it rev on the grades. so long as you have maintained it well and all your fluids are in good shape you won't hurt it.

I actually enjoy the sound of a v8 up in the rom range and working as it's been designed to do.

lots of folks get scard by higher rpm on hills and think they need a diesel because the gassed is working too hard. in reality when towing heavy it's going to have higher rpm. that's just the way it is but your not hurting it to work it like that once in awhile. my .02

 

[VernDiesel]

At 2,500 it should be past lugging so if will hold that gear on its own & does not seem to be straining leave it there. No reason to force down shift if the transmission is working properly.

 

[billyw]

I think you will notice tyranny temps start to climb if you try to keep the RPMs artificially low. For the most part just let the truck decide. No reason to maintain high mph during a long climb either. 3000 to 4000 RPMs is a very comfy range for the 5.7.

 

[Ratket]

What ever you do. Watch the temps.

 

[novelmike]

A few months ago when going up to the mountains with the same trailer, I was in 2cd gear, just sorta cruising up it. My transmission temps did get pretty high. I felt like the motor wasn't struggling to go up it at the speed I was going. My RPMs were mid 2000's if I remember right. Trans went to 245! Coolant didn't go over 212. The temp that day was 95 at the bottom of the will and 3/4 of the way up they were still in the 80's. Once the temperature outside dropped to the low 70's the tranny temp dropped too. But by then I was just about finished climbing any hills and my elevation stayed about the same.

I have since changed my tranny fluid and put a Mag transmission pan on that holds an additional couple quarts.

If I get in a similar situation with tranny temps climbing it sounds like everyone agrees I should drop down a gear and get the RPMs from the 2,000's and closer to 4,000? And even if that means going into first gear?

 

[Rampant]

I keep mine within 500~ish rpm of it's peak torque, starting at the base of the hill. On a stock Ram 5.7, peak torque is around 4500 rpm. If it were me and I had a long hill coming up, I'd manually put it in whatever gear puts me at the speed I want, at around the peak torque and hold it there all the way up.

The last thing I want to do is lug the motor and end up losing speed and then have to play catch-up all the way up. That's definitely hard on the motor and tranny. Not to mention your ego when the Prius club flies by you. It's not a diesel or a turbo, so you need to get it into it's comfort zone, which is near peak torque. If possible, I "get a head of steam up" right before the base of the hill and then just maintain all the way up. Never an issue.

 

[Docpaulo]

Its a hemi... hemis love rpm...its designed for it...

Run the right gear and dont race to the top... your tranny is in more danger than your engine... use tow mode and your truck will choose the lower gear when needed..

4000rpm wont damage your engine... high temps can destroy your tranny particularly since you're in a 1500 vs a 2500

Get a diff cooler/finned cover if your diff temps tend to go high...

 

[rwreuter]

Max torque comes at a specific RPM......shoot for the RPM that provides that max torque, that is where you engine will perform at its peak.

 

[mtofell]

Like the others have said, find peak HP/Torque numbers and let it scream!!

Gas engines are made to rev high for their power. Of course, watch temps but don't be afraid of the high RPMs.

 

[tbaker65]

So on the same note, coming down a hill, its ok (better) to stay in a lower gear, higher rpm, for engine braking?

With my 8sp trans in tow/haul mode, shouldn't the truck recognize the different grades and adjust accordingly?

Thanks.

 

[GsRAM]

So on the same note, coming down a hill, its ok (better) to stay in a lower gear, higher rpm, for engine braking?

With my 8sp trans in tow/haul mode, shouldn't the truck recognize the different grades and adjust accordingly?

Thanks.

If your in tow/haul, yes, additional engine braking is applied, however if the downhill grade is steep, I'd still select a gear manually. Select a gear that provides some engine braking without screaming the engine, 3k ton range is usually where I try to be for good engine braking.

 

[GsRAM]

If your in tow/haul, yes, additional engine braking is applied, however if the downhill grade is steep, I'd still select a gear manually. Select a gear that provides some engine braking without screaming the engine, 3k ton range is usually where I try to be for good engine braking.

 

[Rampant]

So on the same note, coming down a hill, its ok (better) to stay in a lower gear, higher rpm, for engine braking?

With my 8sp trans in tow/haul mode, shouldn't the truck recognize the different grades and adjust accordingly?

Thanks.

I use engine braking whenever possible while towing. Especially on long grades. It will not hurt anything. The transmission is "smart". It will upshift if it hits the rev limiter. Not saying you should allow that to happen, but using engine braking is a no-brainer.

I've never had an 8-speed, but it's pretty safe to assume it is programed similar to the 6-speed in my 2500. To answer your question, yes, it does recognize different grades and adjusts accordingly. If I'm coasting down a grade and tap the brakes, it almost always downshifts by itself. If I don't tap the brakes, it will not downshift until much later in the grade.

 

[Podcast]

OP, to answer your question about RPM as it relates to trans temp a higher engine RPM is better for the trans. The higher engine RPM will causing the trans fluid to be pumped throughout the trans much quicker. This will get cooled fluid back into the trans more quickly and hot fluid to the cooler more quickly.

Think of the engine and tranny heat issues as a dance. The higher engine RPMs will cause higher engine temps yet at the same time it cools the tranny. The opposite happens at low engine RPM. So if you see the high engine RPM causing high engine temps then lowering your engine RPMs may be a good decision IF your tranny temp is already low and IF you can maintain the momentum up the hill.

245 degrees on that 6 speed is WAY too high. My 6 speed never saw temps above 150 degrees while hauling evening in mountainous terrain my typical trailer weight was only 4k. The newer 8 speed tranny's are meant to operate at higher temps and can take that level of heat better.

 

[Rampant]

Transmission fluid (and eventually the transmission itself) longevity would definitely be affected if you ran 245 degrees often or for extended periods. 160 is considered the ideal trans fluid temp for optimum performance and longevity. That is the temp the trans cooler bypass valve opens and begins to flow to the cooler. Elevated temps every now and then under extreme circumstances will not hurt the transmission. Notice the chart above; normal operating temps can reach 284.





From Alldata:
The transmission oil cooling system contains a dual function bypass valve (1) between the transmission and the transmission oil cooler. The bypass valve (1) will bypass the transmission cooler when the fluid temperature is below 70°C (158°F) to aid the transmission fluid to reach operating temperature. The thermal bypass begins opening at 70°C (158°F) and begins allowing fluid flow to the transmission cooler, and is fully open when the transmission fluid temperature reaches 81°C (178°F).

 

[tbaker65]

Good info in those last 4 replies, thanks.

 

[novelmike]

OP, to answer your question about RPM as it relates to trans temp a higher engine RPM is better for the trans. The higher engine RPM will causing the trans fluid to be pumped throughout the trans much quicker. This will get cooled fluid back into the trans more quickly and hot fluid to the cooler more quickly.

Think of the engine and tranny heat issues as a dance. The higher engine RPMs will cause higher engine temps yet at the same time it cools the tranny. The opposite happens at low engine RPM. So if you see the high engine RPM causing high engine temps then lowering your engine RPMs may be a good decision IF your tranny temp is already low and IF you can maintain the momentum up the hill.

245 degrees on that 6 speed is WAY too high. My 6 speed never saw temps above 150 degrees while hauling evening in mountainous terrain my typical trailer weight was only 4k. The newer 8 speed tranny's are meant to operate at higher temps and can take that level of heat better.

Where do you live? I'm guessing you've never towed in 100'+ weather!