My noisey rearend has given me the excuse to change a few things.I've decided to go with a new Eaton posi,stronger axles and a TA cover.I can't make up my mind on gears,I'm going to replace the 4.56 gears with either a 4.10 or a 3.73.I'm leaning towards the 4.10s because of the tall 2.48 first gear with my 4L80E.What do you guys think?

 

4.10. A 3.73 and a 4L80 would be lazy out of the hole with any decent size tire.

 

if u dont care about gas, do 4.10s. thats all that question ever comes down to

 

I've have yet to see a bad axle shaft yet in a truck, Kinda waisting your $ on a set of aftermarkets.

 

Had a friend with 4:10's on his regular cab and that think ate gas like a mug.I got 3:73's on mine and gas is pretty descent.I'll go with the 4:10's if you are looking for performance.

 

How tall are your tires?

These guys have pretty much summed it up. If you care at all about gas, get the 3.73's. If you don't care about gas and only care about performance, get the 4.10's.

I lost 2-4 mpg going from 3.73's to 4.10's, which made it a poor move on my part. Especially because I care about gas mileage.

If you want both (performance out of the hole, and halfway decent gas), get 3.73's, and a tight (i.e. triple clutch), higher stall TC.

 

I'm running 29" tires and a triple disk Vigilante already.

 

Sorry, should learn how to read sigs (*doh*).

You look like a good candidate for the 3.73's. But your best bet is to compute your final drive ratios and see if it's worth getting 4.10's just to compensate for one gear (1st). Second is nearly the same as the 4L60E (1.48 vs. 1.63) and 3rd of course is 1:1 for both transmissions.

 

i'd go for 4.10's in a big tahoe. i only lost 1.5 to 2 mpg going from 3.42's to 4.10's.
but this is in a rcsb truck...

 

From your traction(or lack thereof) post the other day, I believe you have the power now to use the 3.73 even with the taller gear of the 4L80. It may even get you out of the hole better and be a tad safer on the street.