Gear ratio/axles

[Alumbaugh]

I am going to swap out axles due to some damage to my front. have 10 bolt front and rear on a 91 Blazer with 3.42 gears (according to the sticker: GU6) and a 350 - 700r4 combo. All stock. I can go pull axles at a local yard for $150 a piece. Mainly used as a daily driver with 31x10.5R15s. Used to hunt and trail ride, nothing too extreme. would there be any advantage to going for 3.73s over the 3.42s?

 

[AJMBLAZER]

Not really. 3.42's out to be a nicer mpg gearing for 31's. If you ever wanted to go a bit taller or use it as a tow rig 3.73's might be better but you would loose mpg with 31's.

 

[Alumbaugh]

I do tow with it some. allways seems to struggle a little on the hills around. currently get around 17mpg unloaded on the highway. any guesses how much the mileage would suffer with 3.73?

 

[AJMBLAZER]

Well, that isn't bad now. You might loose a few mpg. One of those hard to say things. It'll be spinning faster to do the same speeds but you'll get up to speed a bit quicker. Depends also on your foot and how you drive and your daily drive.

Basically, if you want it to tow a bit better or maybe slap some 32-33's on it some day then 3.73's would probably be a better choice.

 

[chris85]

If it struggles on hills I'd go with 3.73s. I doubt you'd see that much drop in mpgs, but get a little better towing. Just my opinion though. I have 3.73s, I don't know my mileage but I can haul a 14x5 trailer with two 900lb 4 wheelers no problem. Thats also with 31inch tires.

By the way I have the same combo..... 89'/350/700r4

 

[chulisohombre]

its only a 9 percent difference in ratio.should help on hills a lil bit.150 bucks for new running axles is a good deal.it wont hurt milage at all i dont believe.unless you are runnin faster than 70 anywhere,you should be fine.should only be about 200 rpm difference in engine speed.