I'm not sure when the "creep mode" function came out, but it is an option that needs to be ordered with the transmission. I'm also not sure if that can be programmed in later. The 2008 ultra-shift isn't recommended for city driving, only highway. The auto-shift which has the cluck petal to start and stop the truck is recommended for city and construction use.

I'm sure their is a formula on the Eaton website

Their basically the same weight, one has a stick coming out of the top and the other has some small servo's on top of the transmission. The transmission internals and body are the same. The utra-shift still has a clutch, but the computer pushes it in and out. An Allison 3000 transmission is lighter by aprox. 300 lbs. but rated for 370hp or less.

Yup allison transmission or manual transmission are better for off road and slow speed maneuvers.