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Posted

Hey guys. Like the topic says Ive got a 2016 Sierra 6.2 and 8speed auto. Im modding the truck for a buddy. I installed a 5" rough country lift and 20x10 wheels and 305/55r20 tires. Actual diameter is 33.5" I'm wondering if 4.10 gears would be beneficial for performance or if it would just be too much quick shifting? I used a ratio calculator and with the 33s and 4.10 gears the trucks would be spinning 300rpm more at 60mph than when the truck was 100% stock.

Posted (edited)

IMO that's too much gear for just 33" tires

 

Is there an official list of what gears are available for the the rear end that comes with the 6.2? They had 3.23, 3.42, and 3.73 available in 2014 from the OEM. There's at least one guy out there with 4.10's isn't there? What aftermarket support is out there?

Edited by robvas
Posted

I'm thinking we might wait unless I get some more input here. Truck has intake and cat back exhaust at the moment.. But kooks long tube headers/catted y-pipe and black bear tune are next.

Truck currently has 3.23 gears

Posted

I found a better gear ratio calculator. Yes 4.10 would be way too much gear. 3.42 with 33s would put it back to stock 3.23 ratio and oem gears are made up to 3.73 so that would the way to go but probably not worth the $$

Posted

RPM's would be 1604 at 60MPH that's not bad at all with 4.10's

 

RT

Where do u find this stuff at... I wanna know what mine will be lol

 

Sent from my Note 4 on Tapashit

Posted

I have a calculator! LOL

 

RT

How do you calculate dat shiznett hommiii lol

 

Sent from my Note 4 on Tapashit

Posted

4.10s and gm's 8 speed with stock tire diameter basically gives you what Ram offers with their deeper geared zf 8 speed and 3.92's... it would be awesome actually... well but the lack of traction won't be lol.

 

Good luck with finding 4.10's though.... 6.2 trucks and max tow 5.3 trucks have the 9.76" ring gear and not the 9.5"... so 3.73 is as deep as these go using 6 speed max tow parts.

 

Sent from my SM-G900W8 using Tapatalk

Posted
8L90 Gear ratios

First: 4.560

Second: 2.970

Third: 2.080

Fourth: 1.690

Fifth: 1.270

Sixth: 1.000

Seventh: 0.850

Eighth: 0.650

Posted

I'm not sure that you need to change out the gears with 33s. I'm running 35" BFGs with a 6.2L and 3.23 gears and my truck hasn't lost a bit of performance. It does have a tune on it but it does not lack anything. I pull a 7500 lb boat and its almost as if its not even there.

 

I would say let your buddy drive the truck and see if there are any issues. I doubt he will notice anything.

Posted (edited)

I went with 3.73 on mine, had 4.10 on my '12 silverado with 6 spd and yes it made it quite fast but the MPG's dropped a lot, 3.73's with the 8spd is still averaging 16-17 mpg on my daily driving and on a 300+ mile trip I averaged 21.7 mpg and that was loaded down with camping gear (fire wood) and 3 people in truck doing 70 to 80+ mph

Edited by txmuder
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