Mine cam with 3.55's but I have an Indy Ram, the others come with that ratio as well and also I think there is a smaller ratio too.

 

I have a factory sticker under the hood that lists some options including the gear ratio. Yours are most likely 3.55 from the factory for a standard 1500.

 

3:55 is standard 3:92 is an option.
Some of the off road packaged trucks could have 4:11 I believe.

 

Here you go.
Chrysler 9.25
[blockquote]
Application: 1500, 1500 4x4 All Engines

Capacity: 3,900 lbs
type semi-floating
Ratios 3.21, 3.55, 3.92
Ring gear diameter 9.25"
Ring gear face width 1.375"
pinion mounting overhung
pinion shaft diameter 1.88" inner
1.31" outer
Differential pinions two
axle shaft material Induction Hardened
diameter at bearing 1.62"
axle spline pitch 1.29"
Spring Centers 44.50"
Fluid capacity (2/4WD) 4.75/4.75 pints
wheel bearings Cylindrical Roller


I have just recently had Mopar 3.92's installed on my Ram. What a difference even over my stock 3.55's. I am running 285/75/20's. I no longer loose speed going up hills and my acceleration is great. Still not where I want it to be. Thinking about putting in Richmond 4.56's. Paid less than 200 on ebay for the Mopar gears (new) and 300 for the install. No time to do it myself.

As far as the whining in the new gears I would have that double checked. You could loose those in less than 500 miles. It does not take much to destroy a set of gears that are not properly set.[/blockquote]

 

here's an easier calculator:

http://www.drivetraindirect.com/t_gear_calculator.htm

The OD ratio is 0.69. Make sure you use a speed that you would be going in OD like 60 or 70 MPH.

 

Anybody knowa way to re-adjust the shift points togetthe truck back closer to stockwhen you switch to 4.11's?

I'm frantically trying to ingest all the info I can about this before I have it done, and wondered if this was a possiblilty that doesn't require another huge sum of money.

4th gear at 35 seems a little early to me, but maybe that's the trade off.I'll live with it if it is, can't stand the truck now.