M915 series handling on steep hills

[maddawg308]

Anyone here have a M915/916/920/etc tractor that can tell me how these rigs handle going up and down hills? Lotsa up and downshifting? I understand how most big rigs work with the manual transmissions, just curious how these larger MVs do with a load with its semi-automatic tranny.

 

[Hammer]

Curious about this one as well.

And do they downshift fast enough when you are really dropping speed fast on a steep hill (6% to 10% or so) ? Or can you just skip gears on the down shift and make it easier, like in a regular OTR tranny?

 

[Hammer]

Oh, sorry if that seemed like a thread hi-jack! Just seems that one person could answer both questions at the same time (and possibly with the same simple answer.)

 

[AMGeneral]

Well, mine has never shifted below 4th on any serious hill,just as soon as it completes the shift it is gaining speed once again.

Most times it never falls below 45 mph,and that is grossing 80,000 lbs.

Bobtailed or empty trailer,you pull out and pass most of those trucks governed to 62 to 65 mph on ANY hill.

as always,your mileage may vary.

 

[emr]

just guessing but i bet they go down easier...

 

[fasttruck]

Yea EMR they go down hill easier but are also easier to stop owing to the presense of a three stage Jake. drove them back and forth from NJ to Ft Drum with a M872 40' trailer with 2ea armored personnel carriers on and went uo the hills on I 81 at a least 50 mph and cut about 3.5hrs off the trip one way compared to a M818 on the same job.