I looking to buy an 04 2500 4x4 with 4.10 rear with 6 speed manual tranny.
I drove it and and at 60 mph in 6th gear, the rpm was what I expected for a 3.73 rear. I got a build sheet from dealer and was surprised to find truck has 4.10 rear & I looked at sticker in glove box which says 4.10 I'm always on the highway - have another cummins for towing.
Is it possible to have the same rpm with 4.10 in 6th gear as what a 3.73 in 6th. With a 4.10 is the 6th gear a different ratio so the rpm's as same as 6th gear with a 3.73??
Thanks

 

The highway rpm is slightly higher with the 410s (I have an 04.5 with 410s). The difference is very slight. I run a little larger tire and it all works out.

 

Actually, the late 05 and up trucks with the G56 trans and 3.73 gears, tach within 50 or so rpm at 60 mph of the nv5600 with 410 gears. The nv5600 has a little more overdrive.

 

Snodog,
Thanks for the info. Is there a chart or speed versus rpm for the different trannys? What is your highway fuel economy? The price is right on the truck so I'm tempted, but never had 4.10
Jim

 

In my opinion, for unloaded highway driving, they are both under geared. I'm sure if you do a search, you will find a chart. My friend has an 06 with the G56 and I have an 04.5 with an NV5600 and 410 gears. There is no noticeable difference in the two trucks at highway speeds. (we have the same tires)

 

The ratios of the new G56 are a tad lower than the 5600 as well - the 5600 number is first, then the G56:
1st - 5.63 - 6.29
2nd - 3.38 - 3.48
3rd - 2.04 - 2.10
4th - 1.39 - 1.38
5th - 1.00 - 1.00
6th - 0.73 - 0.79
Rev - 5.63 - 6.29

Tire size makes a difference aswell.

Calculator here:

http://www.wallaceracing.com/calcmph.php

 

NV5600 with stock tires and 60 mph.

4.10's 1969 rpms
3.73's 1792 rpms

 

Tire size will have a effect on what you see on the speedo and tach too. Specifically, the outside diameter of the tire.

 

Stock tires.
Thanks for the info. I was ready to buy until the dealer said "there is so much interest in the truck that I'm putting it back on the retail line." 04 with 243K. I checked it over and looked good under and in, drivability was great. So, now he wants $12,500 plus tax.
Cheers, Jim

 

Dang. I paid $11k even for my 04 when it had 80k miles on it. Yes, I keep a grin on, every time I drive it.