So I am looking to change the gears in my 03 QC. I am basically looking for 1/4 mile performance. The truck is driven on the highway, but not a whole lot... it is a daily driver.
So here are the questions.

1. For those of you that have one or the other... what RPM do you turn at 45, 65 and 75 or in that area.
2. Gas mileage effect.
3. Where'd ya get em and did it also require a different speedo gear or is this handled electronically.

Sorry for any naiveness. Any help would be greatly appreciated!!!

 

I don't have 4.56's but I have heard that mileage improves in town and is a little lower on the highway. It would definitely be the best choice for 1/4 mile performance though. From my research I have heard it's only like a 300 rpm increase at the 65-75 mph area. I'm sure others that have done the swap will be able to chime in within a day or two.

 

Hey djr, thanks for the response.. yeah I was noticing the same things since posting and locating the search button . I would like to hear some info on cost of install, cost of gears and where to get them.

 

RB do you have a 4x4?

 

No, its 2wd.

 

1. 70 mph at 2400-2500 rpm's with the automatic.
2. Absolutely no change over stock gear mph going from 3.92's to 4.56's. Much better take-off and around town performance. Better towing capacity. Not as much gear hunting with heavier loads.
3. www.ringandpinion.biz - Jeremy - and required nothing more than the gear and master install kit.

Highway mileage will not decrease unless you think you need to drive 85mph everywhere you go. At 65-70 hwy with combined city, I'm still getting between 17-18 mpg. You *could* have a problem with your driveshaft and develop a vibration. Some do and some don't. I did. Do a search and there is a ton of info on the 4.56's....

 

I recently did this research too. I decided to go 4.10 cause I do a fair bit of highway now and then. A lot of guys here swear by their 4.56's and love them, but also report losing highway mileage above 75. For 1/4 mile 4.56 might be the way to go. I found a thread on DTW that lead to some chart a guy made comparing various gears and ET's. At a certain point your ET's (or was it mph) will start drop with too much gear. If I can find the thread again I will post. On DTW they have a forum section just for gears. Tons of info there.
I didn't put mine in yet so I can't tell you RPM's but prices I got for install range from 250 to 350 for the rear.The cheapest I have found for gears is this guy

http://www.ringpinion.biz/index.php?...40b7c1640507ce

But you also might want to try your local speed shop. That is where Iended up gettingmine. Don't forget to get a full bearing kit too. You won't need to change your speedo. There is a tone ring on your carrier that a sensor uses to read how fast your wheels are turning. Just make sure whoever does your diff keeps the tone ring on.

 

Awesome, thanks for the info guys!!! This is definitely one of my next upgrades. Stump, I actually have been searching around since posting this. Turns out I was just blind and couldn't find the search link originally.

 

Hey guys. I found this the other day. http://3rdstrike.biz/cart/index.php?...roducts_id=621Wondering if it seems like a good deal and maybe if anyone knows what it would cost to have installed. I don't have the tools to do this and my garage won't be finished for about a year.

 

I understand the want for bigger gears i.e. 4.10's and 56's but would picking upthe Auburn andhaveing my stock 3.92sstill show improvement....now i know the durability over thefactory part is way better butperformance wise would it make a difference?