I'm planning on buying an 06 2500 CTD in the next couple weeks but I have some questions about the auto and manual transmissions.

I was originally considering a manual transmission, but after reading several posts about the gearing, I am
reconsidering moving to the auto tranny. Is it true that the G56 is similar to the auto tranny with 4.10?

When I'm on the highway, I usually cruise at around 75 to 80 MPH...I get the impression that this speed isn't ideal for the G56
gearing (someone reported 2500 to 2700 RPM at 80MPH)? Even though the Cummins can handle it, what gas mileage can I expect?
What about running at 80MPG with the auto with 3.73 gearing?

Sorry for all the questions, but this might push me towards the automatic. I actually have an offer in for one of the few remaining manual 2500's
in the state but the saleperson has been unwilling to get down to my price. I guess it's good b/c now I'll have a chance to make a decision on
changing directions! I offered 27,200 on a QC with an MSRP of 37,200 and invoices at 28,000 including 5k rebates but so far, they
are only countering with 28,200. I'll wait until the end of the month and I'm sure it will change!

 

Im auto with the 4:10 gears and I regularly run 75-80 mph. At those speeds the overhead shows 19-20 mpg in tow mode and 24-25 mpg in Crazy Larry setting (BullyDog programmer)....

 

what size tires are you running?

 

The stockers whatever they are, I would have to look ...