4.56 gear on 99 tahoe

[Insanity]

I have a early model 99 tahoe i put 35" tires on it. I have i think a 3.73 gear in it. I want to go up to a 4.56 gear. Right now its got no power in the mud also i don't like how the tranny is working hard for this big tires. Will the 4.56 be easier on the drivetrain? Also, Would these gears be ok on the highway?
And finally, do i have to get my computer reprogrammed with these gears?

 

[GMCYukalade]

Well.. its not gonna be great on the highway.. but it will pull it.. the tranny is gonna still work as hard.. and you can jus buy a SuperChips Programmer and change the gear ratio yourself

 

[95TwinTT]

I have been running 4:56 gears for years. It would give your drive train a bit more mechanical advantage, that you lost by putting the big tires on.

I used the little black box, to change the pulse out tail shaft of the trans. That took care of the speedometer and the computer in one shot.

That makes it easier if you alter tire size again. I don't remember the brand, but I found it on the Inet.

That gear ratio will add a lot of pep to your truck..

 

[Insanity]

95TwinTT

How is your truck on the highway with those gears? Is your truck reving high?

 

[95TwinTT]

My tires are only 30" diameter. At 60 mph i'm turning 2150 rpm's in OD.

Your truck right now should be turning 1500 rpm's with 35" tires and 3:73 gears in OD. If you went to 4:56, you would be turning 1,830 rpm's @ 60 mph in OD.

You were turning 1750 in OD with your old tires @ 60 mph.

 

[Trip]

I installed 4.56 gears on my '99 Tahoe to turn my 35" Mickey T's. The Tahoe is excellent offroad now. Driving down the highway is a different story. As 95Twintt stated: 1,830 rpm @ 60 in OD is right on the money. And speaking of money, it takes alot of it now to move this beast up and down the highway to find an off road spot. I used a Hypertech programmer to adjust the speedo and tranny to compensate for the upgraded gears and tire. At 60mph, I achieve a most excellent 12mpg.

 

[YukonMud]

12mpg is not too bad, for me anyways. That is my best MPG if I drive on a flat stretch of highway, going no faster than 65.
...my average is closer to 10.