Downshift on long, steep uphill grade?

[gwvwadc]

One of our favorite campgrounds is seven miles off the main highway. The road leading to the campground is paved, narrow in spots, winding and has a steep grade for the first four miles. Once at the top, it is approximately two miles along the ridge and then a fairly steep drop into the camping areas.
When coming back out, I know enough to downshift and let the engine braking system do most of the work.
My question is this:
When going up - should I downshift manually or just let the auto transmission make the decision?
Tow vehicle - 2010 F250 with 6.4 Powerstroke
TT - 2013 Cougar High Country

[Seabee]

You will probably get multiple answers because it pretty much comes down to personal preference in the end. Personally, 95% of the time I have the tow/haul button pushed and let the transmission make the decision. On the rare occasion the truck isn't doing what I want then a manual shift is in order.

[PARAPTOR]

Originally Posted by Seabee

You will probably get multiple answers because it pretty much comes down to personal preference in the end. Personally, 95% of the time I have the tow/haul button pushed and let the transmission make the decision. On the rare occasion the truck isn't doing what I want then a manual shift is in order.

X2 when you have the Duramax/Alison combination Tow/Haul button on and let them do their job. On rare occasions when feeling pushed down steep grades nice to also have the exhaust brake on hand. Personally have yet to use manual shift

[shov]

The best way to really answer this is to monitor your Exhaust Gas Temp (EGT) that's your real indication. I am not as familiar with the Power Stroke, but for me I error on the side of caution. If I am pulling a long hill I like to keep my RPM's above 2K and ease up on the throttle. My Allison is pretty smart, but it doesn't know how hot the EGT's are getting.

[bsmith0404]

As others have said it depends. I've pulled many different trailers over different mountain passes and have never had a need to manually shift my Allison. The highest numbers I've ever reached on my truck are: EGT just under 1087, Coolant 213, Transmission 184. That was pulling 9k over Eisenhower Pass in Colorado, outside temps were high 80s low 90s. I had the cruise set for the speed limit. I wanted to see how hot everything would actually get if I just let the truck do it's thing. Those numbers were the peak, but average for the entire climb was probably more around EGTs 980, Coolant 203, Trans 175. If you can monitor your numbers, you can determine what your truck needs to do. I use and Edge CTS to monitor mine.

[Desert185]

If the vehicle shifts up and down frequently during the pull, I would manually lock it in the "happiest gear" for the situation to limit transmission heat buildup.

[Pull Toy]

Plus one for Desert185... but most of the time "Tow Haul" is smarter than me!?! Never yet seen a truck up-shift before it was ready.