trying to research used prostar isx15 best atm, tc10 or ultrashift?

[JimT]

the ultrashift seems to be the most common for non-volvo trucks. I spent 4 years driving a volvo daycab around new england and the NYC and Boston metro areas. For those you definitely need their premium shifter to really take control, but even with the standard shifter it wasn't that bad hauling loads of steel. From what I've heard from other drivers the Eaton Ultrashift is pretty similar to the Volvo I-Shift, maybe even better? Unless I'm mistaken both offerings have the ability for the operator to manually control when to shift and what gear. I think, with the right programming the shift points could be set up to operate in a better rpm range. Sure, probably never as efficient as a good, experienced, caring driver. But lets face it, most drivers are none of those which is largely why fleets are embracing the autoshifts. If you have bad knees or some other problem that makes using a manual problematic then it may be a better choice as repairs to humans tend to be more expensive and painful then repairs to trucks or a slight loss in operating efficiency.

I think one of the biggest concerns about these transmissions when shopping for a used truck is that they tend to pair them with really tall rear end ratios, like 2.90 or worse. Sure you can gear the trans and rears to work together with those ratios but you're still putting more stress on all the components trying to turn the wheels with less input rotations and higher torque. Might be why we (the fleet with the volvo's) saw driveshafts or ujoints break more often with those due to the extra stress at low speeds.

On the flip side, most drivers I talk to like the Ultrashift, as long as it doesn't break down.