Mountain pulling

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What is the proper procedure for pulling in the mountains with an auto tranny, both at hwy speeds and at slow speeds? The reason I'm asking is that both times I have pulled steep grades (lone pine, CA) and Getting up on the Blue Ridge (on the wrong road), I've had to pull over and let the tranny cool down. Both times I was going slow (below 40 mph) and I am just wondering if I'm doing something wrong. Thanks for your input.

mga60tw wrote:in tow haul mode and cruise on will it keep the speed going down the hill? or do you need to use your brakes alot. I have a 2007 duramax, automatic.

With the Allison tranny, you will probably never experience the troubles mentioned here. Its one brilliant piece of machinery. The Allison will start downshifting for you in tow/haul mode on downhills. I prefer the manual mode (Pull shifter to M and use the +/- button) to shift gears just like a standard on steep, curvey/slow speed downhills. The rest of the time I put it in tow/haul mode and forget it.

Now if I could just get a Ford body, Cummings engine and Allison tranny in one truck...

when you put it in second using the manual mode and going downhill will you over rev the engine? will you need to use the brakes in the steep downhills or will the transmission keep the engine from over revving? as you can tell I am new to this towing in the mountains.
will keeping the cruise control on and in tow/haul maintain your down hill speed? or will you need to tap the brakes ever so often?
Thanks for your help

In manual mode you will have all 6 speeds to choose from. No need to go to second gear unless you need more braking. These guys are talking about a Dodge tranny and it doesn't apply to your Allison. Simply choose the gear you need to help hold the truck back at the speed you wish. You will still have to tap the brakes here and there depending on grade but it will be reduced dramatically.

If you don't feel comfortable choosing your own gear then just leave it in drive with the tow/haul mode on and it will downshift when it senses you braking. If you brake harder, it shifts down another gear.
It will not over rev the engine. It will shift up a gear if rpm's reach a dangerous level. (This also applies in manual mode as well. The tranny is smart enough not to allow itself to harm the engine.) Keep in mind the 06 and newer duramax engines can turn much more rpms than the previous years with no damage what so ever.

I would recommend not using your cruise control in steep mountains. The key to keeping a controlable pace down a long, steep grade is slowing down before you start over the mountain. Its easy to speed up if needed but hard to slow down on a steep grade if your approach was too fast.

As for Cruise control keeping a certain speed downhill... I don't know as I never use cruise control in the mountains for reasons stated above. I do know the instant you tap your brake the cruise will turn off and the Allison will start downshifting as needed.

Remember to start slow down those mountains!

Okay, just returned from my trip through the Ozarks, then up to Omaha, and back down to Houston. Peeeelenty of mountains to pull through. Here is my experience with my 2008 Ford F-250 6.4LPSD with torqueshift. It did great! I learned a few things though. First, tow/haul is imperative in the mountains. Actually, up I-40 into Little Rock, I could keep the truck in cruise (while in tow-haul) and it did great. No cruise after that. Too many hills and climbs. Tow-haul worked great. Down the hills, the tranny shifted down as needed to keep the speed. But "coming out" of that downshift was kinda weird. You really had to "rev" the RPM's to get it to "kick out" of the high gear.

I forgot to engage the tow-haul a couple of times after a stop. During a couple of very steep climbs, the turbos were really screaming. I mean screaming. And the loss of power was significant. After I remembered to engage the tow-haul, that never happened again. I did it again on the way down from Omaha (once), and same thing. I will do some more research on this (correlation between tow-haul and the turbo performance).

The main thing I learned was when I could get away with cruise control, and when I could not. But wow, the truck and Cat did fantastic. I have no fears now about pulling anywhere.

Oh...I also learned that Texas has some really horrible roads. I-35 between the Texas/OK border and Dallas, and I-45 from Dallas to about Ennis just absolutely SUCK!

I have a 2005 F-250 with factory installed tow package. I put it
into tow/haul, I've driven ALCAN 5 times, I set the cruise control for
the speed limit (if possible, often you just can't drive that fast) and
drive up/down 10% grades along the way, I've never had it
overheat. YMMV.

Well, I found out over at the Ford diesel site that it was not the turbos that were screaming, it was the cooling fans. Wow...what an experience. The most unnerving thing about it is, the guages on the dash never moved. I know they are mostly for show (and final "extreme" temp swings), but still, to not move at all, even with the cooling fans screaming. Sheesh...I guess some aftermarket guages are in my future!

Tow Haul works pretty good on my Ford. Can not use cruise control on the hills. Without the ability to lock it out of overdrive I lug sometimes. Need to run about 65 with my 30RLBS to to quit that. Wish Ford did not have the dumb idea and take away the lock out on the auto.