This is my first diesel and although I have had it for about 2 1/2 years I am still learning.
This summer was my first tow trip through the mountains of BC so another learning experience. Before this I was mostly pulling on flat lands where I live.

My question is: Which in everyone's opinion would be the better way to tow on flat to moderate hilly areas....setting in tow haul or OD off.
The reason I ask is that in tow haul my truck runs at about 1600 RPM's and EGT is about 1000 degrees on average.
If I switch to OD off my RPM's will increase to about 2300 but my EGT's will run around 800.

MPG's are better in tow haul but I want to know which is better for the truck?

Thanks in advance.

 

Mine bogs below 1600-1700 rpms depending on what I'm pulling so I'd keep it above that, either in tow/haul or OD off.

Also, if I get into a bunch of up and down hilly stuff that makes me shift a lot I take it out of OD and go at around 2000-2300 rpms.

 

I don't use tow haul...

I drive by the exhaust temps. I try to keep the temp to 1000-1100, regardless of gear. i.e. if I"m in 4th and the exhaust climbs over 1200, I'll slow down and/or downshift into 3rd. As I'm climbing the grade, and the exhaust keeps climbing, over 1200 again, I'll slow down and/or downshift.

I was grossing ~18000lb, and found that if I kept the exhaust to 1000-1100, water temps would stay at 220F, on 95-110F days.

I could take 6-7% grade at 40mph; <5% grades were at 65mph or the speed limit.

Tony

 

On my 06 I use tow/haul all the time, I have never used O/Off I live in BC in the mountains and tow a 35ft,8inch 5th wheel and have no problems at all, if your EGTs are at 1000 thats just fine, if it was at 1400 I would be worried.

 

I drove in OD off when going thru the Okanogan as my EGT's and trani temp went up in just tow haul. Both came back down to normal after switching to OD off.

I guess my question was more directed for the health of the truck while towing...not mountains....just normal towing.

higher RPMs lower temps...or lower RPMs and higher temps and better MPG's?
If higher RPM's and lower temps are better for the truck then I will forgo the benefit of the MPG's.

 

Well I tow down to south Arizona for the winter and back home ,Northern BC, for the summer we go over high elevation, mountains, you name it, even driving around town empty I use tow haul, I get better mileage, I service my truck by the book and at 100k not one bit of problems so far. and about at least 50k of that is towing. The Okanogan is a lot hotter there than here. more RPM seems to cool EGTs I do have a double deep trany pan which helps, and a deeper rear diff cover.