On another thread, engine/transmission weight was discussed. For instance, my 8V-71T and V730 weigh in around 3,300lbs. A series 60 with liquid included and a 10 spd transmission is tickling 4,000lbs. My light weight favorite is the Cummins ISL and 3000 series Allison. Engine- about 1800lbs wet and the transmission about 600lbs wet. 2400lbs is a whole lot lighter then 4,000lbs.
With the new Eaton Roadranger UltraShift Plus-the transmission has an electronically controlled clutch that allows the transmission to shift in about a half of a second-quite a bit faster then the original UltraShift or AutoShift. With that also, Eaton has finally listed the complete transmission with clutch weight, and it is rather eye opening (course this is without oil). The 10 spd is 915lbs and the 13/18spd is 978lbs. Compare that to the Allison 4000 series at 831lbs and the 3000 series (good to 450hp and 1250lb/ft torque) at 535lbs. But-you'll get the best fuel mileage with the 13/18spd UltraShift Plus. Good Luck, TomC