4.56 gears on the way

[mudryder18]

I am in the process of getting my gears done, and wanted to know if anyone has put 4.56s in their expys? If so what size tires are you running and what kind of mpgs are you getting. Also what rpms is the engine running around 60-70mph.

 

[nvycrmn]

have you looked into 4.88's? i do not have new gears in mine yet, i am still running 3.55 with 35" tires and i get about 10mpg (needs a tune up though) and sitting at 2k rpms at about 65-ish. if i had to guess, i would imagine it would probably be close to something like that with the 4.56 and the 37's.

i know....doesnt answer your original question! hahaha

 

[mudryder18]

Yes i was debating between 4.56s and 4.88s, but talking to several friends and getting recomendations i went with 4.56s. I didnt need 4.88s since i mainly do all pavement drivng and only occasional off roading. Yea i was running my stock 3.55s with 35s for 2 1/2 yrs and then got 38.5s and had them for a year before my rear end finally gave in. That is what is prompting me to get gears now.

 

[nvycrmn]

ahaaaa. you gonna throw a selectable locker in there while you have it apart?!

 

[mudryder18]

No im just puttin in an upgraded yukon limited slip. didnt have the funds for a locker.

 

[walnuts4x4]

I had 38s and 4.88s on my old 97 F150.... look in my album... and loved it... drove it from upstate NY border near canada to south New Jersey... a lot of times and got close to 17mpg with a 4.6.... currently have 3.73 in expy but when I have cash gonna do 4.88s... I think 4.56 are better with 35s and 4.88s are better for 37+

 

[mudryder18]

Walnuts- thanks for the input, i was really considering 4.88s but i decided go with the 4.56s due to my mechanics advice and several friends. hopefully i can get 17mpg with my new gears, i would be ecstatic with 14mpg. i also have a k&n cai, straight pipe exhaust and a superchips programmer that i can put on 87 octane mode.

 

[nvycrmn]

when you get those 4.56 stuffed in there, let us know what you come up with as far as gas mileage and rpm numbers...

 

[mudryder18]

Yea i will. i guess ill have to since it seems ill be the first one on here with them.

 

[nvycrmn]

look at it this way, you are the pioneer! hahah