Toyo310

I have read on different forums that the Allison MH2500 transmission is a very light duty transmission. And, that on most coaches it is at or over it's load limit. However, I have never read anything about the failure of one of these transmissions. If you had a failure or know of one please let us know what failed and the reason for failure.

The issue for me is really not the performance of the 340hp but the fact that the 2500 is at its limit. So the coach with the 340 and 2500 is limited to 33K GCWR and the only way to change that is replace the transmission with the 3000. If I remember correctly the 2500 transmission is limited to 660lbs of input torque. So, you can not turn up the hp and torque of the 6.7 340hp without risking damage to the transmission and the GCWR can not be increased above 3300lbs.

I have a 2104 allegro RED with the 6.7 340 hp and 2500 transmission. I towed a Toyota 4 runner which was around 4500 lbs and my coach is 29500 lbs. I traveled out west and north up into Canada. The coach did fine as far as transmission temperature, engine temperature and overall performance. Long grades slowed me down but I was always keeping up with the flow. At times some people passed me, however there were times that I passed others. I always use the shift arrows and down shift long before the transmission automatically down shifts. When I am in mountains or very hilly roads I limit the transmission to 5th gear and at times have limited it to 4th gear to reduce the slow down on long grades. I had the transmission serviced at 30,000 miles and the tech said that the fluid looked new and there were no indications of abnormal wear. With all of that said I don't have a problem driving it this way and am ok with the performance. However knowing what I know now I probably would have purchased something with at least 360hp and 3000 transmission. This is my first class A coach and I wasn't aware of the options. But it's not worth the money to trade up now because of the slight inconvenience of having to help it shift.