Hello,
I have an '04 Dakota quad cab with a 4.7. I have already done airrade intake, fastman TB, and flowmaster exhaust. I spoke with a guy here locally (Phoenix, AZ). He recommended I put better/improved gears in the truck along with Posi (Sp?). It is going to cost around $1,100 for him to do the job.

My question is this-Is it worth it?
Also the only chip/programmer made for my vehicle is Jet. I have heard bad things about Jet, could anybody give me feedback about the gears and do you know of any other programmer out there that would work for my truck?

 

what size gears do you have in it now? I have 3.55 in mine but a 3.75 would be a nice gear. not too high and not to low. I think the 3.92 would be too steep if you do alot of high way driving.
I got my rearend rebuilt last year and I kept the 3.55 cause I do alot of highway driving. it costed me around $1000 that was with a trannyflush added on to that.
________
PAXIL CLASS ACTION LAWSUIT

 

Hey joba Before you get new gears what size are yours? Like Johnny said if you do a lot of highway driving try and keep them low. The only reason I want to get bigger gears on mine is because I like to offroad a little bit and I'll get a lot more torque to the ground with some 3.93's or bigger. I have some puny 3.55's but they get the job done. Another thing to consider is do you plan on towing with your Dak and if so how much weight? Do you want to have a fast 1/4 mile time or a reliable Dak with better gas mileage? These are all things to consider when deciding on the gears you want hope it helps.

 

MG - I too have the 3.55's and am planning on going to a larger gear. You hint to smaller gears being more reliable, could I assume the opposite for larger gears, would they be "less reliable"?

 

I was just saying as far as a DD that's not trying to race around and gets the best possible mpg out of these trucks should stick with 3.55's I have never heard of other gears being inferior in the sense that they would fail on you.

 

The 3.92's will cause your engine to spin at higher revs, which puts more wear on it and the tranny compared to a 3.55 equipped vehicle. You're talking about a 10% difference in ratio, so it's not going to be anything you'll really notice on the wear side, but power wise yes, it makes a difference. I've got 3.92s and I wouldn't consider anything lower. Yeah, I went through $160 worth of gas on Monday alone, but I don't think the 3.55s would have gotten me much better mileage, and I do tow a ~6000 pound load around every couple of months it seems.

 

There you go then LOL. It's all just based on your needs and what you want your Dak to do.

 

So when going with higher gears a few questions.

1. If you go with a larger tire size in conjunction with the larger gears, will it even out the revs in the motor? I read on another website that if you have 33 inch tires and 4.65 gears (I think is what it said) it makes the same ratio as having stock tires and 3.55 gears.

2. Disregarding the first question. If yours revs will be higher by going with a larger gear, does the tranny compensate by shifting sooner? So say your cruising at 45 @2000rpm with 3.55 gears. If you had 3.92's would you be holding 45mph say @2500rpm or would it shift to the next gear?

3. How much does your top speed decrease by going to higher gears? I generally don't ever break 80 (I drive my cage like a grandma). Any idea what the top speed of say 4.10's would be running 32inch wheels?

thanks all

 

You would be able to run at 80 no problem you would just be running higher rpm's. I'm not sure about the change in tire sizes and how it would affect you. I don't know what your top speed would be but I have been up to 110 with my 3.55's with plenty more tach to go so I think you'd hit the speed limiter before topping it out. Propably when you change gearing and tire size you would just have to have the pcm reprogrammed for the change then everything would shift at the same intervals but I'm not sure about that...

 

Shift points are pretty much set by RPM and load, not MPH. So if you shifted before from 2 to 3 at 35mph you might now shift at 30-32mph, but it'd be the same RPM range.

I've hit over 100 with 31s and 3.92 gears with plenty of pull left.

If you want to keep the same ratio as stock but increase tire size to 33" then you'll need to run a 3.77-ish gear, which nobody makes as far as I know.


If you want to run a 4.56 ratio then you'll need to step up to a 40" tire.

unless my math is off anyway.