Have an existing I shift AT2612D direct drive attached to 2.47 rears I would like to drop the ratio on this truck to the 2.1s and add an ishift with crawler gears. The rear ratio change is straight forward, but can you upgrade that ishift or any ishift to have crawler gears?
Basically what I am asking about is that the newest Volvo trucks have implemented turbo compounding and crawler gears to overcome the startability issue of super quick ratios that allow for extreme downspeeding and fuel savings. Is it possible to add crawler gears to an existing ishift or would I need to source an existing ishift with them already on it? If this is possible, crawler gears, how quick can I take the rears on an overdrive unit and what would be my limiting factor?
You would have to swap transmissions. But there’s also a chance that the electronics are not compatible. Some of the newer data-buses are faster then the older ones.
Would not do anything less than the 2.47 you have in it. The turbo compound makes better torque on the low RPM and that is why the 2.1's work on that. They have to have the 13 or 14 speed with crawler to get started but it will not work well in your set up. Will run to low RPM for that engine. Also would have a hard problem finding away to fix your shifting for that set up since it is all from the electronics package you have.
