Posted this on the Allison Tran. Forum already but thought I'd also put it on here for more input.

Recently traveled from NW Ohio to the Black Hills and then onto Yellowstone. I have an 07 Itasca w/8.1 Vortex and the 6 speed Allison. I was towing my 3300# PT cruiser on a dolly. I noticed while in the high alltitudes, steep grades and long pulls, my transmission seemed to howl. It was very noisy in the cab area. It was not the cooling fan as I have heard that before in this unit and my previous coach.

The excessive noise disapated when we got to lower altitudes and flatter roads ie: Illinois, Indiana and Ohio.

Any help would be appreciated. This is a new unit with about 4500 miles on it.

It is your clutch fans kicking in due to running the coach at high rpms and lower gear.

Thanks Gramps! By the way - the name "Gramps" has very special meaning to me. My Grandfather who was like my own father was called Gramps. So - anyone named Gramps is always right in my book. (Even though I am 64)

I would have to agree with "Gramps" the fans can be a loud as a C5 comming at you head on.

Fred