NV5600 vs Gertag gearing/fuel economy

[favord]

A buddy is looking at getting a new ride. We just test drove an 07 2500 6spd. shortbox. I've got an 04. 5 3500 with 6 spd. I noticed at 75mph. it seemed the 07 was running about 2400-2500rpm. I'm pretty sure mine runs around 2200rpm at similar speed. I couldn't tell you what the gearing is in the 07, pretty sure mine's 3. 73. I'm not sure of the exact height of my aftermarket tires but they are just slightly taller than stockers. My buddy is just curious about the difference and potential fuel economy concerns, etc. in the 07. Anybody have any insight or advice?



Of note, as we pulled out for a test drive, I told him not to expect too much snap from the motor since they are pretty tight and my 04. 5 seemed sluggish for about 20k when I got it new. He got on it and that stock truck had some pretty nice snap - I was amazed.

 

[klenger]

The 6 speed in the new trucks is a MB G56, not a getrag. That out of the way, look at the gearing charts on my website at http://www.klenger.net/dodge/general-reference/gear-speed-calculator.pdf or http://www.klenger.net/dodge/general-reference/gear-speed-calculator.xls for the Excel version. The G56 is only available with the 3. 73 axles, and the final drive ratio is about the same as the NV5600 with 4. 10s. Expect a small reduction in fuel economy, but not all that much.

 

[drewRoberts]

NV5600 and 4. 10's here. . . if I turn my TST down and keep off the skinny pedal I can almost hit 20mpg, however there is no fun in that so I leave her crunk and stay all over that skinny pedal with my size 13. 5's. . . funny thing is I still get 17. 5mpg hand calculated



she may never go fast. . . but she sure does get there in a hurry :-laf

 

[favord]

The 6 speed in the new trucks is a MB G56,

That's what I thought but salesdude said Getrag. . ???



Thanks for info. Kind of what my SOP feel told me but probably not enough to really make a difference.