I was told you need to run these tractors over 1800rpm to get enough lube for the trannys. I have a 500 vers and i think its the biggest pos i have ever had. No lugging power, noisy,and gross on fuel, the old n14 cummins is 100x the motor. There is a reason why the trucking industry is running from the. Also the cummins dealer/ company are a bunch of a.. holes.
There are some other threads on CF about not running the TA22 below 1800 due to reduced Trans pressure and therefore flow. There are so many different design limit features built into tractors now it is hard to know if you are getting "full rack". But assuming you are from power % meter and the fact it pulls the load, there still is the fact that as rpm goes down torque load goes up to do the same amount of work. For example on my MT965B if at full peak power of 565 hp at 1650 rpm would be 1800 ft lbs of torque on the crank and internal transmission components. That is from the torque formula of hp x 5252 divided by rpm. If you drop one gear and increase rpm to 1800 the torque drops to 1650 ft lbs. Drop two gears and run 1950 rpm and torque drops to just over 1500 ft lbs. These are at 100% load and not typical for all day numbers so that is where you need to decide how much torque do you want your components running at for what % of the time. My 59' 5710 drill with 450 tank and 3000 gal nh3 pulled at 60 - 80% so I ran at 1650 in 9th gear which is at 80% load occasionally and calculates to 1439 ft lbs. Seems in range and the engine loved that speed. On a hilly 1/4 I dropped one gear and run 1800 rpm. Easier on everything.