Gears?!?!?!

Sierra5.3 · February 8, 2004

Ok Im in a dilemma.... I am going to re-gear my truck for the 35's I have added to my lift.... Now I wanna know what gear should I use? 4.10 or 4.56

Ill do alot of driving in it....No towing, rarely.... Im gonna add a supercharger when the weather warms up... and headers and electric fans..

I dont think im gonna put bigger tires on... I just want my power back...

So whats the verdict??

Tex2kZR2 · February 8, 2004

4.56's easy..

4.10's will give you some power back but your tranny is still gonna hunt for gears going up hills and inclines. That's why I would go 4.56

Mule · February 8, 2004

I did 4:56 with my 33's, so you will need at least that with 35's. 4:10 wont show much of a difference over 3:73 (at least not worth the price).

Make sure you recalibrate the speedo and shift points for the new gears.

JRider · March 4, 2004

Definately go with atleast a 4.56 ratio. I am going with 4.56 gears in my Avalanche and I only have tires that physically mease 32.25". With 35" tires it isnt even a question. I do a fair share of towing and hate the constant downshifting. 4.56 should take care of the shifting for me and also help out the whimpy 5.3 (by mechanical advantage).

If you go with 4.56s at 80mph (typical highway speed in MI) you would be winding 2453rpm. 4.88 would be 2625rpm at 80. This all asuming your overdrive to be .7 (as it is on my Ave). Try this link...it may help you.

http://www.quiknet.com/~ke6vut/rpmcalc.html

Take care,

JRider

Chad H · March 4, 2004

Definately go with atleast a 4.56 ratio. I am going with 4.56 gears in my Avalanche and I only have tires that physically mease 32.25". With 35" tires it isnt even a question. I do a fair share of towing and hate the constant downshifting. 4.56 should take care of the shifting for me and also help out the whimpy 5.3 (by mechanical advantage).

If you go with 4.56s at 80mph (typical highway speed in MI) you would be winding 2453rpm. 4.88 would be 2625rpm at 80. This all asuming your overdrive to be .7 (as it is on my Ave). Try this link...it may help you.

http://www.quiknet.com/~ke6vut/rpmcalc.html

Take care,

JRider

So with 4.56's what would my silverado's RPM's be at? Let's 75MPH.

JRider · March 4, 2004

A 285/75-16 tire converts to 32.8"....different brands may be slightly larger or smaller...from my experiences they are usually smaller than the standard numbers they convert to. Anyway, to answer your question...2454.6 rpms at 75 mph.

Take care,

JRider

Mule · March 4, 2004

Look here:

http://www.northern4x4.com/cool%20stuff/ge...ear%20chart.htm

JRider · March 5, 2004

That chart is good info...just remember the 4L60E trans (1500 Avalanche) has an overdrive so the ratio is not 1:1...more like .7:1. Now that I am considering a suspension lift and approx. a 34" tire I am thinking I should go with 4.88s. Anyone interested in buying 4.56s new in box? I am not one for a gutless truck and gears make a huge difference.

JRider

Chad H · March 5, 2004

PM sent, I want those gears!!

Mule · March 6, 2004

That chart is good info...just remember the 4L60E trans (1500 Avalanche) has an overdrive so the ratio is not 1:1...more like .7:1. Now that I am considering a suspension lift and approx. a 34" tire I am thinking I should go with 4.88s. Anyone interested in buying 4.56s new in box? I am not one for a gutless truck and gears make a huge difference.

JRider

Right about the overdrive. Mentioned in the paragraph above the chart.