I know you got the 06, I'm just saying I wouldn't get another one with a ZF in it. They're like women, they can be fun at first, but you can expect monthly hiccups, high costs down the road, and the eventual urge to kill it.
I got to drive a buddy's 06 LBZ/Ally to California loaded to about 16-18K, and thoroughly enjoyed it...for an automatic. but the mpg sucked, we only got around 10 mpg.
As good as the Allison is, I gotta do my own shifting, so this is just the way things are. Manual transmission loyal to a fault.
I think most of the ZF6 issues are guys that turn them up, I think with stock power and some PTO covers with more capacity, she will be fine.
More stockers failed than ones turned up. And I would GURANTEE you that a ZF truck wouldn't have gotten enough better MPG to have noticed. I know personnal preference is one thing, but I don't see in wasting money to do so. It would be one thing if we were talking about a DODGE slushbox, but were not.
Temperature isn't the biggest killer, that will help some but you still have to over come the weak clutch and cheaply made Synchro's that cost at least your left nut to replace.