Gears

[jeepers149]

I have a 1997 z71 with 33s . I know new years are not exactly necessary but to add performance when I get a 3 inch lift what would be the best gears to get. I don't ever pull a trailer or anything . I just want more speed and gears that'll make it easier on the tranny

[mainechev]

4.10s would be good or 4.56s would be fine if you want a little more performance.

What gears do you have now?

[daved931]

4.10 gears would be ideal. If you have 3.73 gears now, it's not worth the money to upgrade.

If you go to 35" tires, you should upgrade to 4.56 gears and that would be worth the money.

If you have 3.42 gears right now, it might be worth the money to go to 4.10. Again, if you're thinking you might go to 35's, then you should go to 4.56.

[96ImpSS]

What tranny?
With the 4L60E, my opinion as far as general guidelines for decent performance with little to no hit to MPG's:
29" tires: 3.73's
31" : 4.10's
33" : 4.56's

The astute readers will observe that the ratio's between those tire sizes and rear gears aren't equivalent. As you get to bigger diameter tires and lifted trucks, it actually benefits mpg to give it more overall gearing to push the added mechanical and aero drag.

[jeepers149]

i have the factory 3.73"s . i v been thinking of going 4.56 but just wasnt sure

[Quyonmob]

The astute readers will observe that the ratio's between those tire sizes and rear gears aren't equivalent. As you get to bigger diameter tires and lifted trucks, it actually benefits mpg to give it more overall gearing to push the added mechanical and aero drag.


^This is key. The basic math of RPM at XXmph is only part of the equation, the above is the rest, and equally important.

[mainechev]

What tranny?
With the 4L60E, my opinion as far as general guidelines for decent performance with little to no hit to MPG's:
29" tires: 3.73's
31" : 4.10's
33" : 4.56's

The astute readers will observe that the ratio's between those tire sizes and rear gears aren't equivalent. As you get to bigger diameter tires and lifted trucks, it actually benefits mpg to give it more overall gearing to push the added mechanical and aero drag.


^This is key. The basic math of RPM at XXmph is only part of the equation, the above is the rest, and equally important.

:word:

[94_c/1500]

What engine is in the truck? If you have a 350, then I suggest for your truck 4.10s or possibly 4.56 gears since you after a little more performance. If it's a 262 or 305, then get 4.56 gears at least.

[tahoe 9955]

imo 4.56

[Low97tahoE]

imo 4.56

x2

[1Ton-K1500]

before i completely re-did my truck, i started with a 4" rancho susp lift and 33's. bought the truck that way with 33's. great fuel eco with the gears that were in it...pointless 3.42's (i haul a lot). no trailer on my trip to canada got 17.5mpg at 75mph, if i remember correctly at 65mph the tach was at 15-1700. after i broke them i jumped to 4.10's loved them, still got 16mpg and at 65 tach was at 2100, great for passin on highway right in power band. they handled the 33's just fine, could burn them off all day, the problem was in the mud anything deeper than 6 inches of mud you would HAVE to be in low range. If i were you and dont pull anything, i wouldnt go any more than 4.10's, tranny will hold as long as you have replaced the reaction sunshell carrier(if not already done by GM in the recall) any steeper and you will be complaining about fuel mileage--not good with expected $4 gallon this summer. thats my two cents

[Quyonmob]

1Ton-K1500, your math doesn't work.

Assuming 700R4/4L60E trans:
3.42 w/ 33's @ 75mph = 1828rpm, likely a touch higher as a 33" tire rarely measures 33" mounted.
4.10 w/ 33's @ 65mph = 1899rpm, ditto...

Did you mean to compare them at the same speed?

[1Ton-K1500]

yeah just to give an idea of rpm difference.
3.42's @65=15-1700rpm
4.10's @65=2100rpm
Little clearer?

[Quyonmob]

yeah just to give an idea of rpm difference.
3.42's @65=15-1700rpm
4.10's @65=2100rpm
Little clearer?

Nope. Math is still broken for 4.10s. Either your 33's are only 30" tall, or your TC isn't locking up.


4.10 w/ 33's @ 65mph = 1899rpm

[94_c/1500]

yeah just to give an idea of rpm difference.
3.42's @65=15-1700rpm
4.10's @65=2100rpm
Little clearer?

Correct your speedometer for taller tires and lower gears?

[94_c/1500]

before i completely re-did my truck, i started with a 4" rancho susp lift and 33's. bought the truck that way with 33's. great fuel eco with the gears that were in it...pointless 3.42's (i haul a lot). no trailer on my trip to canada got 17.5mpg at 75mph, if i remember correctly at 65mph the tach was at 15-1700. after i broke them i jumped to 4.10's loved them, still got 16mpg and at 65 tach was at 2100, great for passin on highway right in power band. they handled the 33's just fine, could burn them off all day, the problem was in the mud anything deeper than 6 inches of mud you would HAVE to be in low range. If i were you and dont pull anything, i wouldnt go any more than 4.10's, tranny will hold as long as you have replaced the reaction sunshell carrier(if not already done by GM in the recall) any steeper and you will be complaining about fuel mileage--not good with expected $4 gallon this summer. thats my two cents

Why would you have to use low range because of your 4.10s compared to your 3.42s? Or did I misunderstand and you meant that the other way around? By putting it in low range, you are making it even lower geared. Your logic only makes sense if you meant using low range with 3.42s is comparable to 4.10s.

And lower gears don't have to mean worse fuel mileage, in some cases it may allow better gas mileage.