towpro wrote:
skipro3 wrote:
I have a 2006
Have you considered the manual tranny. I have the taller rear end gears and rarely have to shift down from 6th even climbing mountains with a GVW of over 12,000 pounds and running 19.5's with 34" tall tires. When I do down shift to 5th, it's because the road speeds are 55mph or less on the twists and bends while climbing.
Manual makes for good speed control on downhills too.
Skipro, your 2006 was the first year for the G56 manual trans.
in 06 the G56 has 0.79 OD. in 07, maybe before the 5.9 went away, it was changed to .074
06 with 3:73 = 2050rpm @ 65.82mph
07 with 3:73 = 1900rpm @ 65.12mph
now the Aisin has 0.63 OD
18 with 4:10 = 1800rpm @ 65.93
18 with 3.73 = 1650rpm @ 66.43mph
My 06 also had the G56 manual, running 2050 rpm @ 65mph
and my current 2015 runs 1800 RPM @ 65mph
and my new 2018 will run 1650 RPM @ 65mph.
With the 2018 model year, it appears you can only get 3:42's unless you order a dually, than a dually with the Manual you can get 3:42's or 3:73 but not 4:10.
My truck with the 19.5's and (approx)34" tall tires turns 1800 rpm at 65mph. I use a GPS because the speedometer and odometer are 10% off now.
