rockcrawler304

I am stumped. I have a 2006 Mega Cab with CTD 4x4 and 6 speed. I am turning 2300rpm at about 72mph. When I bought the truck 3 weeks ago I thought it had 3.73 gears cuz that it the standard ratio. I am now thinking I have 4.10 gears from the RPM I am running. I have looked at the window sticker and it does not say anything under the options section for the different gears. I have also looked everywhere I can think of on the truck and cannot find the answer. No tags on these axles for some reason. Aside from the old "jack it up and turn the tire method" does anybody know what I have or where to find it??? I did search and did not come up with anything. Thanks for the help.

CrazyCooter

With those RPMs, you have 3.73's. 4.10's would get you 250 more RPM.

packard8

Yup, the new G56 box is geared lower than the NV tranny it replaced. I keep looking for another gear everytime I get past 60 MPH It's a great tranny when towing heavy but it sux running empty on the freeway.

rockcrawler304

I feel the same way!! When I hit the freeway go to 6th and start crusing, I keep wanting to shift one more time. From what I heard is that they don't make any taller gears yet either for these axles. I would love to go to a 3.54 or 3.31 gear because the heaviest towing I do is a Jeep on a trailer or an RV camper. I guess I'm stuck for a while.

ptgarcia

Mount some larger tires (35" or so) and it'll get better.

P.J

I only have a few hundred miles on mine and I've tried to shift into 7th about 10 times now.

As stated, a bigger set of shoes will help that out when the time comes. It's a whole lot better than being under geared. It's going to be good for my towing too, like an incentive to keep it below 70 mph. (fuel savings wise)

bubba33

with my auto and 373 it is running about 2000 rpm.taller overdrive then the new 6 gear.

ptgarcia

You're absolutely right, because with the power of the Cummins its so easy to climb past 70 mph while towing and not even realise it. Last weekend I found myself cruising at 70 with my 8000 lb travel trailer in tow, forgeting it was back there (a long day at the beach will do that to you), and putting on my blinker to move over and pass traffic that was going 70+ mph! Its just too easy to go too fast with this much power under the hood.

Hounddog

I WISH the NV5600 had a LOWER reverse.Backing a heavy trailer in a lot of situations reverse is TOO TALL.

dieselengineer

I agree, that is why I changed out the front hubs to free spin lockout. Now I can crawl back in low range. A walk in the park

SolarYellow05

dieselengineer,

Did you use the dynatrac conversion kit?

P.J

My reverse is granny, I also prefer it that way though. Makes is so you don't have to totally ride the clutch while backing.