Just joined and need help. My new 06 2500 6 speed is suppost to have a 11:50 ring gear. Never heard of this before. Big Horn Pkg. list Anti-Spin Differential and 11:50 ring gear. Does this mean I have a 4.10 axel.
Cummins runs 1900 rpm at 60mph. Bought the truck to pull a 36 ft. 12000 lb
fifth wheel travel trailer.

Thanks in advance.
Tom in TN

 

Well here's a big DTR hello, and welcome to the site.
Check to see if there's a sticker inside the glovebox door.
Most later years have the 'build sheet' specs on that label.
Mine does and shows I have a 4.10 gear.

 

That sounds like the # of teeth on the pinion and ring gear. Doing the math on it though ( 50/11 = 4.54) doesn't sound right, especially for a diesel. I wonder if the 11:50 is really 11.50 indicating axle size?

 

Just a shot in the dark here, but wouldn't that more than likely mean his ring gear is eleven and a half inches in diameter?

chaikwa.

 

Yeah, the janitor is right, it is ring gear diameter.

 

That means that you have an 11.50 inch diameter ring gear made by AAM. It sounds like you have the 4:10 ratio if you are running 1900 RPM at 60 mph.

 

The '06 with the 6spd is only available with the 3.73.

MikeyB

 

I was right?

I WAS RIGHT???

Yeehaw! I answered a question with a correct answer for once! I guess there's a first time for everything!

And thanks for referring to the proper title and not 'maid'!

chaikwa.

 

Maybe we will get some decent coffee around here, if this you getting things right thing continues

 

he's right too ^^

 

11.5" ring gear is the diameter of the ring gear, no relationship to the # of teeth or gear ratio.
10.5" ring gear is std on the 3/4 tons w/ the gas engines.
On the 06 model 2500's and 3500's (don't know about the 1/2 ton trucks), any CTD truck will have the 11.5" rear axle. The gear ratio is not shown anywhere attached to the truck on the 06's, not in the glove box, no tag on the axle, no sticker under the hood. There are 2 gear options: 3.73:1 and 4.10:1. If the window sticker does not list a gear ratio under the options, it's a 3.73. If it's a 4.10, it will say so listed as an option.
Why there's no identification on the vehicle anywhere, I don't know.