i have no problem with stock (3.92) gears and 35's... still beats my brother's sierra. lol.
mine says the gear ratio in the glove box... not sure if they did that in '06
Have you looked into install prices? i was quoted at about $800 for install, then add the price of parts... ouch... dont get me wrong, i still WANT them, and with all of the towing I do in the summer i will probably need them... wish i could install myself
What kind of lift are you getting you lucky SOB?

 

Im doing the Fabtech 6" and 3" PA body lift.

 

You should be able to do better, local shop here is $600 per axle for gears, install kit & labor...


That's a LOT of lift for an IFS truck. I know the Fabtech for the '02-'05 torsion front ends were pretty bad with the CV angles, but I've heard the '06+ coil over kits are better about it. Still, if you are going that high and plan on going to 37" tires or larger, you need to learn how to change a CV axle if you don't know how to already...

 

Nah I want to stay with 35's. I think ill skip out on the PA body lift.

 

Im wondering what rpms are all of you running on the high way with 4.56 gears. like when you are doing 70 on the highway. can you even keep it under 3000 rpms. Im sure that there is a whole lot of get up and go but if your not taking your truck to much off roading and your running the high way is it really worth running it at those kind of rpms. i personally dont have a lift on either one of my trucks i just want to understand why people are gearing to 4.56s.

 

if you have 33" or larger wheels, 4.56s will work wonderfully. your truck will feel like it should have from the factory. with 34" wheels at 75 mph i am turning around 2200+/- rpms

 

That's the rap those who have not re-geared believe. Somewhere, sometime, some idiot with stock gears said something about rpms being crazy high on the interstate.
Truth of the matter is, I'm running about 400 rpm higher at 70 mph with 4.56 gears than I was with 3.92 gears. My in town mpg's is up about 2 and my interstate mpgs is down about 1. Overall power to the rear wheels - priceless...

 

I agree with Hammer. I have 4.56 gears with the stock 275/60r20 tires, and at 70 mph, I'm only running around 2200-2300 rpms. And at 80 mph, I'm at a little more than 2500 rpms. Like Hammer said, the added power to the rear wheels is nice. That is the main reason why I put in the 4.56's, since I am not putting bigger tires on. Well that and the fact that I wanted a Trutrac, and said what the hell, while the rear end is opened up I'll add gears, too (even though it cost more since I had to do the front gears as well). For me, overall combined city/hwy mileage has stayed pretty much the same.

 

well that is the reason i asked. I was just wondering but if that is all your getting then great. so when it is all said and done your getting more low end torque. if i understand what you are saying. thank you both for your time and your comments i hope i never pissed anyone off that wasnt my intent i was just wondering.