Swapping rear gears..Do I really need to swap the Front as well?

[hillbilly2084]

Thank for the help. I have an auto tranny, it is kinda hard to get going from a stop but not to bad imo. I usually dont drop down gears on the highway. Towing the boat though puts a good strain on the truck. Would regearing help on my mpg? I am gettting approx. 10mpg right now after a full tune up. Thanks again.

[Loki]

you want to change them both...the front and rear output shaft on your tcase will end up spinning at differant rpms and you'll end up tearing something up in the box. 4.56's would be a nice jump from the stock 3.73s

[Redz Z]

Thank for the help. I have an auto tranny, it is kinda hard to get going from a stop but not to bad imo. I usually dont drop down gears on the highway. Towing the boat though puts a good strain on the truck. Would regearing help on my mpg? I am gettting approx. 10mpg right now after a full tune up. Thanks again.

Hmmmm... Since you tow, your mileage is pretty poor, and your starts from a stop are pretty hard, I think you would be a good candidate for a regear. that mileage is pretty horrible for a tuned Vortec 5.7L with 35s. You should at least be 12-14mpg.

This would be my advice-

1. Keep an eye open for a junked IFS truck, 1/2 or 3/4 ton 6 lug with 4.10s. You should be able to find one; Especially since so many guys are now doing solid axle swaps and their IFS stuff just sits there, it shouldn't be that hard. I would imagine you could buy the front and rear axles complete rotor to rotor for not a penny more then $500. You could bolt it all in within a weekend. I would give it a 3/5 wrenches in terms of difficulty. It would also be a good time to think about a suspension lift if you are considering it, since it will be a lot of redundant work to change the axles out.

2. Regear your current axles with aftermarket gears to 4.56s. This would be anywhere from $1000-$1200 installed. A 4.56 wasn't a factory option but it would probably be the best for you. It will be more expensive though then a self performed axle swapout.

So, it's a 4.10 with a cheaper overall cost but more work for you, or 4.56 with new gears installed at a higher cost. Either one will give you better results in terms of towing, mileage and drivability.

Keep in mind that in going from 10 to 12 MPG, it is going to take you a LOT of miles to payback the cost of gears at a payoff of a few cents per mile.