I put together a fleet of '05-'06 GMC C4500's with the 300-hp Duramax and the Allison automatic for a former employer for route trucks. That was a good combo, darn near bulletproof, and they shifted just fine- bearing in mind it's a TRUCK drivetrain not a Cadillac. Only real problem we ever had was the tires- these used the 225-70-19.5 lo-pro tires, GM spec'ed a Bridgestone M724 all-position type tire on all six and we had vibration problems that never went away. The dealer switched wheels and tires around the axles, rebalanced, etc and the trucks still would shake so bad a couple of drivers refused to drive them over 45 mph. I finally had the leasing company swap out the fronts for Michelin X rib-style steer tires and they drove like glass forever after. 'Course you couldn't rotate front to rear anymore but the Michelins wore like iron.
And yes, they did have a Park position.
Sic gorgiamus allos subjectatos nunc
http://ohioccwforums.org/ Ohioans for Concealed Carry:THE source for Ohio CCW information and discussion!
The allison in my 2500HD doesn't have a "real" park position -- my manual was very clear on that -- and it's true -- you must use the parking brake, as if you don't, and it's on an incline, the tranny can jam in park.
The allisons on the RV and the 24' box truck DN have park.
And for the support of this Declaration, with a firm Reliance on the Protection of Divine Providence, we mutually pledge to each other our lives, our Fortunes, & our sacred Honor
I am beginning to be concerned about our '06 Commander, which is currently at the dealer for [strike]some[/strike] yet another transmission woe. And I think that the issues are definitely affecting suppliers, because I called another dealer yesterday about a new radiator for my Wrangler, I was told that they were severely backordered, which doesn't surprise me, since the original went out at about 49K miles, and the aftermarket "upgrade" didn't even last for 30K.
Cognosce teipsum et disce pati
"People come and go in our lives, especially the online ones. Some leave a fond memory, and some a bad taste." -Aesop