It looks, from your sig, that you got those damn 22's off and put 18's on with a nice set of Toyo's. GOOD MOVE. Freakin' 22's on a 4x4, Geesh!!! Anyway, your factory 3.55 open diff. is an attempt by DC to get better MPG ratings (taken in un-realistic, perfectly level, low speed, low resistancesimulators) and better smog/pollution ratings (lower RPM's = less emmissions). In real world driving, this gearing sucks, plain & simple. You are underpowered and towing capacity is diminished, and despite the lower RPM's you actually burn more fuel in all situations except possibly high speed interstate cruising! The 3.55's would only be an acceptable gear ratio if you had a light truck with smallish tires(2wd, single cab, 31.5" or smaller meat) once you have a quad cab OR 4x4 OR larger tires, then a step up to 3.92's is logical. Any combination of the above could mean a step higher than 3.92's would be required for optimum performance. In your case, you have a QC, 4x4 with 33" tires and are not getting anywhere near the performance you could have, this coupled with the fact that you don't have the added torque of the Hemi would require a dramatic increase in gearing. If you plan on staying with the 33's and NEVER going larger, then 4.10's would be the minimum you should consider, giving a good balance of power and fuel economy. 4.56's would not be a bad choice either, and if you are going to consider larger tires at some point then it's the 4.56's for you. If you decide to change the gears, then it's a good time to do the aftermarket LSD, as most places won't charge any additional labor, since they are inside the "pumpkin" anyway. I know this ain't gonna be cheap, my move to 4.56 gears, front & rear, plus Auburn LSD ran me a shade over $1400 for parts, labor & tax. But to date, it's the single best mod I've done from a performance stand point.
Here is a link to a guide for proper gear ratio's, you'll see that your ideal gear ratio falls right in the middle of the 4.10 & 4.56 gears. http://www.4wheelparts.com/gear_ratio.html

 

I've got an 02' QC 2x4 4.7 Auto with 3.55 gears (No mods yet). I would like a leveling lift, nothing too big its just a 2x4, and some bigger tires down the road. And would like a trailer. Not a toy hauler or anything, but I would like a decent trailer. I know with a 4.7 I'm limited and later down the line I would like a CTD just to tow with, but $$ isn't there for it yet. I was thinking of going with 4.56 gears. What do you guys think? And what kind of cost am I looking at for this. I asked the dealer the other day when I was in there and he said something in the neighborhood of $1300. I thought that was steep for a 2WD.

 

4.56's would be great with bigger tires and a huge plud for towing. $1300 is way out of line for rear gears. Like I stated above, I had 4.56's installed front & rear, master install kitAND Auburn LSD in the rear for a little over $1400 with tax. Motive 4.56 gears for your rear end with master install kitis about $250 and the rest would be labor which I figure $300 would be afair estimate. So, you should be able to get it done at a reputable installer for no more than $550-$600.

 

Hammer, thanks alot for the advice, sorry it took so long to reply back I just got back into town this week. I have got another question. You said you did both the front and the back gearing?? Is that worth the money, or if you dont do it how does it affect the driving at highway speeds in 4WD. Thanks again.

 

Also what is a good/reputible brand for gears?? Thanks again

 

Must do front & back in a 4x4. If you don't and engage the front drive shaft & it's a different ratio than the rear, the tow truck driver will have to go backand getyour shattered transfer case and other various drivetrain parts off the road after he hooks up your truck.


Gears are probably the single component that you will see the biggest argument about on a forum. No matter what brand you say, somebody will post a horror story about, and tell you what crap they are. I firmly believe that this is because no other component in your truck is as hard to install as a set of ring & pinion gears, and when someone screws up the install and they crap out and take the whole rear end out, it's always the ****ty gears fault.
I have Genuine Gears, and you will read dozens of posts on how noisy and crappy they are. But I have a lifetime warranty on mine, and they have been as quiet as my factory gears. That said, though, I believe Motive Gears have the best reputation.
Just find someone who does gears on a regular basis to do them. I know good mechanics who can do everything else in your truck, but subs out gear work.

 

Way easier method: put one rear wheel on something slick (wet grass works very well). Give it some gas, but don't nail it. If it moves, it has LSD. If not, the diff's open. And that's the diff :-)