Hey guys, I am trying to figure out what gears are possible to switch out in my 9.25. My local guy said he could do whatever I needed in a month or so but is swamped right now so I wanted to hear from you. I have an 02 1500 with 3.55 gears and need something taller after engine and tranny swap. Looking through online suppliers I see they have a 2.74 and 2.94 for 9.25. I wasn't sure if this was the same rear end that I have or not. I would be interested in the 2.94 and am not sure if I would have to change a lot of the axle out or if it would be a straight forward swap? Obviously I've never done anything like this so any help would be appreciated.

 

Your going the wrong way. Taller=numericly higher gears. I went from 3.55 to 4.56. I also run slighty taller tires. Going down smaller numbers the truck will not get out of its own way. Higher gears will make a huge difference towing and getting going from a red light.

 

It's best to use the terms lower or higher, or speak in terms of ratios (as in numbers)..

Taller speaks of higher gears, or covering more ground with one rotation.. shorter speaks of lower gears, or covering less ground with one step.. its argued the other way too, though.. those terms aren't very clear..

The op said taller and quoted ratios, so I'm guessing he wants higher gears? .. interesting.. as counterintuitive as it sounds, higher gears aren't going to help your mileage.. lower gears will.. the math argues, but the reality is that the engine doesn't have to work as hard running lower gears, especially when starting to roll...

 

I do understand what the different gears do. The truck has a cummins and 5 speed in it. I use it as my daily driver to haul my tool boxes around. I have never really used 1st gear and while shifting normally am starting 5th gear around 45mph. When going down the highway at 60mph it is running almost 1900 rpms. I just got the tach in and haven't been down the interstate yet to see what my rpms are yet. I have been avoiding the interstate because at 70 to 75 it sounds like my engine is going to explode. I know I'm not really hurting the engine but I'm sure you can understand where I'm coming from. I know running taller tires would change the gearing a little, but it's only a 2wd so I don't want to go crazy.

 

I didn't realize you were running a diesel... Your torque down low should be enough that you can drop numerically, where us gassers don't reach the torque you have off idle until we're way over 2k rpms.. and you obviously make that torque quicker and stronger than us gassers..

You'll likely be fine dropping to 2.73/2.75:1.. but not for significant towing or hauling.. you'd want at least 3.55 for anything over three or so thousand pounds, or you'll be lagging big time..

 

This truck will never be used to haul more than a couple atvs at highway speeds. I have a 3/4 ton for bigger loads. This truck is mainly used as a car with tool boxes. Playing with gear calculators I figure something around a 3.08 would be about what I'm looking for so I think if the 2.94 swap is possible it would work great. Now I just need to figure out if it's even possible.

 

Tires were mentioned... You can fine tune the drive ratio you're aiming for with the tires.. get close with gears, dial it in with tires..

 

If your other truck that you haul with is a 3/4 then what is that Cummins on?

 

It's a 12v cummins that was put in a half ton. A retired diesel mechanic did it for fun. Now it's my daily driver. It gets around 25 to 26 mpg if I keep the rpms around 1600 which is about 50mph. But driving it 60 to 65 every day its only getting around 20 which is the reason behind this idea.

 

This is what i hoped you would say.... im already in love we would love to see some pics! Or at least i would. This has been my dream for a while!