I just got my 06 3500 CTD with six speed, and immediately had 285 tires put on it and had the dealership recalibrate it before i ever picked it up (supposedly). My question is at around 75 mph i am pulling 2400 rpms, is that right?? Sure seems like it revs up high. The dealer told me it had a 3.73 rearend, but i can't seem to find the gear ratio on the doors or anything. Is sixth gear just fairly low?? Sure hope i didn't get 4.10's . What is everyone elses expereince with this?? I just got rid of an 03 ford 6.otoh and at 75 it only pulled about 2100 rpms, 80mph around 2250?? Just wanna make sure i didn't get 4.10's somehow, otherwise i really like the truck .

 

That's why I bought the auto. I took the G56 6-speed out for a cruise and the RPM's were higher than I expected. That is with the 3.73's. I don't tow more than 4k most of the time, so running in the higher RPM range for more torque was not an issue.

I put a lot of Interstate miles on. In Iowa and Nebraska, that means 75-80mph which means 2400-2700 RPM's.

As a lot of people hear have said, when I got to 65mph, I was trying to find 7th...

I'm pretty sure you got 3.73's, unless 4.10's were listed on the sticker.

 

Nope, Youve Got 3:73s 2400rpm At 75mph Is Where Im At Too. Just The Gearing. Ive Just Learned To Deal With It.

 

Axle ratios are listed on the inside of your glovebox.

 

4.10s aren't available with the six speed.

 

ok good, thanks for all the good info. hard to beleive these trucks can get 20mph when they are revving up that high. Hopefully i will be getting 18+ once broken in?? Thanks again, this is a great site, will post some pic. when i get some taken.

 

You probably won't get 20 with it unless you stay at or below 60 mph. Faster than that and the mpg seems to drop off pretty quick with the "600" motors. Mine will just barely get 20 running 60, goes down to neighborhood of 17 at 70.

 

DC decided to save a nickel. No sticker in the glove box on 06's. At least, not on mine.

 

another place to look is on the axle tags they will have a spot where they are indicated as to what ratio you have.

 

Put taller tires on. I have 245/19.5s which are 34 inches tall and it helps bring the RPMs down.

 

When I see number like this I am glad to have a 305/555 and an NV5600, I get over 20mpg consistently unless I run the whole tank over 70mph. Best tank was about 22mpg.

Nick

 

Something I saved:
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 - 5.74

 

I have 4.10s and a six speed

 

You don't have a G56 trans eaither.4.10 not offered with the G56 trans.It was with the NV5600.

 

So what trans is the standard 6 speed, and which trans is the HD one? I know when I bought mine (went auto) but they had standard and heavy duty? Sure seems the G56 is harder to get parts for ect. Just currious.