truckin-on

Just ordered a 2010 3500 Laramie SRW w/ a stick and 3.73s. Now I'm wondering if I really should have stayed with the 3.42's. Anyone have the ratios in the box? I remember seeing the auto ratios, but never the stick. I assume they are not the same as the auto.

-truckin-on

redruM Hauler

1st - 6.29 -
2nd - 3.48 -
3rd - 2.10 -
4th - 1.38 -
5th - 1.00 -
6th - 0.79 -

ridofpwrstroke

The ratio for sixth was changed i think late 07. I think it is now .74 for sixth gear. It depends if you ever plan on running 35's. If you do, keep the 3.73's or if you are going to tow heavy. You are going to be real close to 2000 rpms at 68 I believe. With the .79 in my truck, I am at 63mph at 2k.

truckin-on

What is the sweet-spot RPM-wise for the Cummins running light vs. towing? I haul a fairly decent sized 32' 5th wheel, probably go nearly 10k fully loaded.

My current truck is a 7.4l big-block Chevy w/ a 5-sp OD manual and 4.11s in it, and I'm trying to sort out what would work best for me with the new CTD.

It looks like Dodge rates the 3.73 for 2k more GCVW and trailer weight over the 3.42 gears. Don't totally understand this, as I would assume you would just pull in 5th rather than 6th, which would be a stronger gear anyway as it's straight-through 1.0.

-truckin-on

Spooler

Get the 3.73 gears pulling that heavy and I assume the truck will be a 2wd. Backing up and starting off will stink with 3.42 gears. 3.42 and pulling in 5th i beat you will loose MPG. The sweet spot for me towing is 1800 to 2200 Rpm.

truckin-on

OK - thanks. I think I'll leave it with 3.73's. Should be enough cogs to choose from hopefully! It's a 4WD by the way...

MikeyB

The latest version of the G56 should have a .74 OD.

MikeyB

AH64ID

That is the AD ratio. It was changed in the end of CY06 (Early MY07).

The current AE ratio's are:

Gear Ratios:
First: 5.94
Second: 3.28
Third: 1.98
Fourth: 1.30
Fifth: 1.00
Sixth: 0.74
Reverse: 5.42

ridofpwrstroke

It depends on how many times you tow a year and how many times you drive it empty. I would go with the 3.42's if you tow down roads that have a 65 or 70 mph speed limit even with a 10k load. The 6.7 has great low end even compared to my 5.9. If you are going to tow mostly at 55mph or 60 and tow alot, I would opt for the 3.73's. You wont notice a huge difference between the two gears backing up or taking off.