Understanding I-shift and rear end ratios

I pull 63,500 and I am positive that is the same spec as mine. Running 105km is in 12th and revving 1450-1500 or so. It will lug down to 1200 and shift and keep downshifting around that 1100-1200. If you let it do "it's thing" the $$ icons appear a lot at those lower rpms.

 

Yep, it just keeps lugging down and shifting. You can select "economy" or "performance" where performance will rev it higher and shift faster. Or just pull the shifter to manual and shift it up/down as you want. Crest the hill and back to auto or get out of the mud/ice/snow and slide back to auto is what I do.

 

I just picked up my vnl430 with the xe package you've described. I built the truck to haul wood chips (super b) in bc interior, coast, and kootenays. How it works is low gears allow 1650 torque, mid gears 1850, top gears 2050. Having a lot of 6-10% stuff to deal with, I was initially scared of being overgeared but was willing to risk it for the performance the truck would allow when cruising at highway speed. A good chunk of my day is cruising at 100 and hammering over rolling hills which is where this truck shines. At 100km/h with 11r22.5 tires youll be cruising at 1275 rpm and I believe 1600rpm in 11th. Peak torque is at 1000rpm and drops off after 1600. Take it for a spin, I took a chance on it for my application and Im glad I did.....cant wait till its broken in and we're on summer fuel again. Only drawback is being overgeared for the harder pulls (7%+) anything less will keep you in those peak torque gears where you will fly. So far this truck is spanking our fleet of dd15 western stars and freightliners and doing it with much less fuel, and its only got 15,000 km on it!

 

Also, the I shift is fantastic. No suprises in the muck either - I pulled my traction control module and run in manual mode most of the time and it hasn't let me down yet. There is a button to limit the traction control intervention when in mud, snow, on ice etc but I prefer it 100% disengaged at all times for maximum control.

 

AT- direct 1-1
ATO - OD tranny

AT2412C - Auto transmission, 24NM TQ rating, 12 Speed, C- version