[skyking650]

Hi Tom,

Thanks for the advice. Yes, I checked the specs of the 4000MH transmission and it is rated to handle up to 2644 TQ and 800 HP in the motorhome application. The stock ISX 650 is 650HP and 1950 TQ. Here is a chart from Allison......

http://www.allisontransmission.com/docs/...f?sfvrsn=2

Not positive that I will put the tuner on this coach as it accelerates fine as is, but I have had real good response from these tuners in other motorhomes including significant gains in MPG, most recently in an Entegra Anthem with the 450HP ISL cummins. Shifted better, accelerated better, and had instant gain in MPG. Not interested in motorcoach racing, but any gain in performance with a gain in economy with no ill effects sure sounds like a win win for us.

Thanks again,

Tom