How Much Of A Difference Will I Notice...

[onac255]

I just recently put some 285/70/17s on my truck and I really like them except for one problem...

 

My truck is an absolute dog of the line now ! I have 3.42 and I am wanting to go with 4.10s.

 

My old mileage was about 18 Mixed (85% highway) at 60MPH I could push 21-22 (Pretty Flat interstate here in El Paso)

 

But with these new tires I need to figure out my mileage again. I'm guessing it must have gone down to about 18-19 highway.

 

Now If I go with 4.10s will the difference be night and day as far as acceleration?

 

I know mileage will suffer but I am wondering how much.

 

Right now with the 3.42, My engine speed is 1986RPM @ 70Mph how much will the 4.10s change that?

 

Thanks in advance fellas

[97SierraGMC]

you didnt put on that big of tires so i would suggest 3.73's.. unless your planning to go bigger later

[onac255]

I know what you mean but I really want some 4.10s for the acceleration and towing because I really do not tow anymore with my truck because of the $hitty 3.42s (Long Traumatizing Story)

 

And If Im only gonna lose 1-3 MPG I could live with that if the performance is there but if it ain't then I will just stay with what I have now.

[97SierraGMC]

i would stay with what you have ....

 

for $1000 its going to cost to put new gears in your could get other performance stuff that would help as much if nto more..

 

Intake, Exhaust, Tune....

[VMax2007]

Right now with the 3.42, My engine speed is 1986RPM @ 70Mph how much will the 4.10s change that?

 

Thanks in advance fellas

 

4.1/3.42(1986 RPM) = 2381 RPM

[onac255]

$1000!!!??!?!?!?!?! WTF? Who told you that?

 

I already have a price 340 for the parts and I can do the work myself (My Dads owns a CV Axle/Power Steering Shop) Even if I didn't do it myself the total cost for parts and Labor is 800 @ 4 Wheel Parts and The local 4X4 shop place charges 720

[onac255]

Right now with the 3.42, My engine speed is 1986RPM @ 70Mph how much will the 4.10s change that?

 

Thanks in advance fellas

 

4.1/3.42(1986 RPM) = 2381 RPM

 

 

Awesome! Thanks Jeff

 

Do you have 4.10s in your truck Jeff?

[onac255]

Anyone else?

[VMax2007]

Right now with the 3.42, My engine speed is 1986RPM @ 70Mph how much will the 4.10s change that?

 

Thanks in advance fellas

 

4.1/3.42(1986 RPM) = 2381 RPM

 

 

Awesome! Thanks Jeff

 

Do you have 4.10s in your truck Jeff?

 

 

Nope, 3.73's. They are sufficient, but if were to do it again, I would have gone with 4.10's. Too bad they are no longer even an option now.

[2000DV4.8]

Go with the 4.10s, especially if you can do the labor yourself (just make sure you have someone there that's done it before).

 

You won't notice a huge difference between 3.42 and 3.73, but the 4.10s will really help off the line, with towing, and would probably increase your city mileage a little bit.

[onac255]

Me and My dad have changed out gearing on quite a bit of 4X4s and recently an 05 Avalanche. So yeah that helps that I can do the labor myself.

 

85% of my driving is highway though so how much of a hit am I gonna take with 4.10?

[Tucson_02Silverado]

Did you have the tire height changed in the ECM?

 

Is your speedometer showing slower than before? Check with a GPS or stopwatch and use the freeway milemarkers

[97SierraGMC]

yea.. even though i went from 245 stock on my truck to 265 my gps is right on with my speedo

[merlin5577]

With the 4.10 gears and larger tires you will lose approximately 2-3 MPG's. IMO if you drive mostly highway save your money for other things. Even at $340 (dont forget the front axle too) and doing your own work, thats $340 worth of gas, plus the lost MPG's. Not only that, by running lower gears (400 rpms by Jeffs math) and bigger/heavier tires mostly highway your increasing wear and tear on the engine and transmission. If you did mostly city driving the gears would help you get up to speed quicker so it would be a different story. Just my $.02

 

Either way good luck Ivan.

[onac255]

Did you have the tire height changed in the ECM?

 

Is your speedometer showing slower than before? Check with a GPS or stopwatch and use the freeway milemarkers

 

My speedo is off (Can't find my predator) but not by much according to my GPS

 

With the 4.10 gears and larger tires you will lose approximately 2-3 MPG's. IMO if you drive mostly highway save your money for other things. Even at $340 (dont forget the front axle too) and doing your own work, thats $340 worth of gas, plus the lost MPG's. Not only that, by running lower gears (400 rpms by Jeffs math) and bigger/heavier tires mostly highway your increasing wear and tear on the engine and transmission. If you did mostly city driving the gears would help you get up to speed quicker so it would be a different story. Just my $.02

 

Either way good luck Ivan.

 

Thats $340 for both front and rear gear sets my tires are already 285/50/17 and I do not plan on going bigger until they where out which will won't be for a long time hopefully.

 

I really think I need to regear though because with the 285/70 this truck really feels like its working harder just to move...