6 Speed Allison transmissin
Hi to all fellow travelers, My wife and I recently purchased a new to us HR diesel pusher. It is a 98 with a Cummins and the 6 speed Allison tranny. In general the transmission shifts very smoothly...
Forum Discussion
FIRE UP wrote:
Ct,
While I wouldn't be too concerned, a call to Allison or, to a service center for Cummins/Allison of your choice might settle your mind. Ours does quite often, a harsh 5-4 shift, if, conditions are just right. If we're cruising in 5th in a grade and slowly loosing speed, enough to cause the trans to jump to 4th, it can sometimes "jerk" the beast around a bit. Remember, the available torque at a given RPM, can and will be felt during some shifts.
On the up shifting, most of the time from 1-2-3-4-5 and finally 6th, it's usually pretty darn smooth but, it's on the down side that, can cause a bit of a shake every now and then.
Exactly the way ours works.
