LARRY01Z28

iTrader: (28)

Ive got a 2005 Silverado 5.3l with bolts ons and a cam. Ive got 323 GU5 and G80 in the rear right now. future mods are a stall and gears. going with a 2600 or 2800 stall.
I'm wanting to put a 3:73 or 3:90 gear in. which one would be best?
whats the best gear and install kit to get? a buddy said summit racing gears,usa standard ,or Yukon????
ive got a local guy to do the work for me. thanks for the help.

FFDP

iTrader: (2)

What kind of driving will you be doing?

Is this an everyday truck or just a weekend fun toy??

Do you care about fuel mileage at all?

If I wanted an all around gear without going crazy and still wanted to bum around at 70mph on the freeway at a decent rpm, I would install 3.90's with a tru-trac. Yukon gears I've heard and read are just fine.

I know people will comment and say go 4.10's or 4.56's yadda yadda but it comes down to what you want to use it for. And I know people say they get such and such mpg doing whatever speed but in the end they are never always driving like a grandma going to the grocery store.

Wolftrk99

iTrader: (5)

Either ratio will be a night and day difference over the 3.42s you have now, difference between 3.73/3.90 is really not enough to really be noticable, id agree with FFDP on the 3.90, personally have had good luck with 3.73s but at times wanted a bit more!!!

wyo307

As far as a gear manufacture I would go with Richmond or Yukon, I currently have a set of Usa gears in my truck and the backlash variance was way out of factory spec I went ahead and ran them and they are a little noisy

LARRY01Z28

iTrader: (28)

I think im going to go with the 390 gear. i just feel like it will be better suited for me. i drive my truck about twice a week. maybe 750 miles a month. so gas mileage is not a factor. i have a worktruck for work and daily driving.
it is the 10 bolt. GU5/G80 which i looked up and it says 3:23 gears.
so i think it would be a big difference.

when i order i order for the 8.6 right?

LARRY01Z28

iTrader: (28)

also do i use syntheic fluid for break in?

Wolftrk99

iTrader: (5)

Use what eaton says to with the trutrac.... My eaton posi called for mineral oil... Which i need to look up exactly what again i need to chnge my fluid...

LARRY01Z28

iTrader: (28)

my parts guy ran my vin # and he said I had 2.73 gears. but my RPO code says GU5.
so I guess im going to pull the cover and do the math. lol

FFDP

iTrader: (2)

The RPO code is right.

They never offered that gear ratio in your truck. 3.23, 3.42, 3.73's and 4.10's are the standard gears.

LARRY01Z28

iTrader: (28)

kind of what I was thinking?? im just going to order a set of gears and a install kit. new seals and fresh fluid and go with it. lol