Yup...they call that "gear fast, run slow" I've worked for a few outfits like that...one down in Texas had me driving a 2006 petercar...475 Cat, 10 speed (but ya drove it like a 9...stupid thing would shift itself between 9 & 10...usually at the wrong time ) and 3.36 rears...ran fine on flat ground. Can't say anything bad about the jake on the downhill side...but going up, it was never pretty. I partially blame the transmission, though...because it would not shift from 10 to 9 until it was lugging...no "anticipation" to be able to get the turbo wound back up before it would be lugging in 9th...so then you would shift to 8th...and sometimes catch it "between" gears...it would be in the hole, but not in gear. So, by the time you got it into a gear that would pull the friggin hill, you were in 6th...and being a 10 speed, the steps were too large between gears so there was no "working your way back up through the gears" to get back to the 8th or 9th gear that SHOULD have been able to pull the hill if I could have shifted it like I wanted to. That or it would be in 10th gear pulling the hill just fine, and RIGHT before topping the hill, it would downshift to 9th...then, instead of accelerating back up to speed, it would rev way up, realize we were now on the backside of the hill, and go back to 10th...but of course in the process of doing that, you lost at least 2 truck-lengths to anyone else pulling the hill along side you. Then I went to work for a company out of Memphis, in a 2005 freightshaker...435 mercedes, straight 10, 3.55 rears. I was running EMPTY across I-68 and would have to downshift to 7th to make it up some of them hills. Loaded sucked. Needless to say, when it came time to buy my truck, I spec'd it more like the log truck I used to drive...the one right before those other two. I can run an 80,000 truck across I-64 in Indiana and never downshift. If I want to avoid lugging, I can split it to 17th...still don't have to move the shifter, though.