I just noticed that our coach has the Allison HD 4040R transmission
The 295 and 270 of the same year (2000) have the HD 3066R transmissions
What is the difference? Is it significant?
Both are excellent 6 speed transmissions. The difference is the HP/torque that they will handle. The 4000 is used with higher HP/torque engines, the 3000 on lesser HP/torque engines.
The 4000 series is the heavier duty transmission of the two. see attached for specs
Rick, Thanks for those spec sheets, I notice the date on the 4000 Series is May 2008, that must be when they approved it for the ISX engine 650 @ 1950.
My 2001 4000 Series does not have that high rating, I had to get into that issue when I had the ISM moved up to the 500 @ 1550, which it will handle correctly but that is the upper limit for that year model I was told.
FWIW