The new Allison 2500 series has overdrive IIRC from when I was buying my bus from the dealership. The odd thing is though the guy said they get the same mileage and same top speed with basically the same rear axle gears as the older buses. They just get there quicker. Now I understand how 5 gears could help with acceleration, but not how the overdrive wouldn't help top end unless you were actually starting to run short on power. He said the 2500's are often found behind the school bus duty C7 Cats and they run a 4.56 gear usually with a top speed around 70 on the new computer controlled buses. Now I know I would be happy to get the 8mpg at 70 mph the new buses are getting, but he said they were doing the same thing with the last of the AT545'ss
Any thoughts on that one? I still think a bus would benefit from a 2500 series Allison in terms of strength, and the gear options, but the cost is high, they need a computer, etc. Was this guy just blowing smoke up my backside or what?