2014 GMC Sierra 4x4 5.3 final drive question

[jmansfield04]

Hey everyone,

New to this forum and have come here for some insight. I have a 2014 GMC Sierra 4x4 5.3L with 3.08 gear ratio and 265/70R17 tires. I live in Maine and do a lot of towing with a 4500 pound trailer. The state has lots of hills/mountains and I find my Sierra constantly downshifting/hunting for gears on the highway. I'd like to change my gears out to 3.73's or 4.10's. Right now with the 3.08 traveling at 80Mph I am at around 1850RPM. If I go with 4.10 gears and keep the stock tire size what RPM will I be running at 80Mph? Would 4.10's be too much, or should I go with 3.73 gears? Not looking to go with larger tires.

 

Thanks,
Josh

[CamGTP]

Use an rpm calculator.

 

The 6th gear ratio for a 6L80e is .66 if I remember right. At 80mph with the stock tires it would be ~2160rpm with 3.73's.

 

https://purperformance.com/p-29669-rpm-calculator.html

 

I would stick with 3.73's with the 6 speed auto. New gears and then tune it and you'd be all set.

[jmansfield04]

Thank you

 

[truckguy82]

On 10/18/2021 at 8:50 PM, CamGTP said:

Use an rpm calculator.

 

The 6th gear ratio for a 6L80e is .66 if I remember right. At 80mph with the stock tires it would be ~2160rpm with 3.73's.

 

https://purperformance.com/p-29669-rpm-calculator.html

 

I would stick with 3.73's with the 6 speed auto. New gears and then tune it and you'd be all set.

Which would be pretty much the same thing as him just leaving his trans in m5.

[truckguy82]

On 10/19/2021 at 8:39 AM, jmansfield04 said:

Thank you

 

Dont get gears, a tune would help more with that

Edited October 23, 2021 by truckguy82

[CamGTP]

I'd still want gears.

 

Anything he listed would be better for towing. Getting up to speed and cruising speed. If he plans to keep the truck a long time it would be worth it.

[truckguy82]

On 10/23/2021 at 7:24 PM, CamGTP said:

I'd still want gears.

 

Anything he listed would be better for towing. Getting up to speed and cruising speed. If he plans to keep the truck a long time it would be worth it.

It really just helps with first gear imo

 

i mean he’ll just shift to second gear sooner with gears