3.08 vs 3.43

[yukon25008.1]

X2.. 4;10,s

But really regardless of the motor i dont ever want anything less then 3;73.. I have 4;10,s now with a 5spd allison

And its perfect! even with the 33" tires!

[yukon25008.1]

If you drive something with 3;73 or 4;10,s and get into something with 3;08 you will be unhappy!

[Babyhauler]

3.42. will be better in town. Mine is used like a car most of the time. My 3.73 drove better in neighborhoods & town, the 3.23 are better on the interstate. Better mileage, not performance. If I was pulling a trailer, they would suck. But I dont, so they are okay. I wish I had 3.42 in my crew cab. They would be a happy medium. A 6 speed with 3.42 would be really good for me in town & school traffic.

[zibzer]

IMHO, I do not believe the 3.08 should even be available in these trucks. My old 4.3l truck was a dog with 3.08. I had the option of replacing it with 3.73 or 4.10 and I decided to do 3.73 as I was unsure how mileage would change. Well, mileage was the same with the 3.73 but man what a difference in acceleration, towing and general drivability! If I could do it again I would have gone 4.10. But I certainly would not want the 3.08 back. Keep in mind this was a 4 speed with a 200hp motor, and I'm not sure how the 6 speeds feel with the different rear ends. I had a 5.3l with 3.42 and I would not want anything less. A 3.73 or 4.10 would have really made that truck hop.

[bartonjude]

3.42

[gdl]

Thanks everyone, I've decided on the 3.42!

[yukon25008.1]

If you ever go with a larger wheel/tire or just want a little more bottom end there are plent of threads in here about going with 4:10.s or 4:56,s

[yukon25008.1]

you have to remember a 3:42 with a stock tire is ok..As soon as you go taller or say to a 33" your back down to a 3;23/3;08

[tyhuck]

...

[Jutty_Z71]

3.42 is your best bet, that is what I have on my 2011. The salesman actually tried to talk me out of it saying that I didn't need it and I would get better fuel economy. I pointed to the Honda dealership across the street and told him I would be there if I cared about MPG's, and that I actually use my truck. I agree with others that 3.08 should not be available on these trucks, but 3.42 is fine. What alot of the guys forget is that 3.73's paired with a 4 speed...the 3.42 is paired with a 6....it all balances out.

[Badass69]

No it doesn't balance out. 3.42 in the rear is still just 3.42...... Your 6 speed beyond it's stupidly low first gear and it's two overdrives has 3 really useable gears..... and on the highway usually just 2 much like the transmissions it replaced. There is a lot more to a vehicle than just initial acceleration from a dead stop.

 

More mechanical advantage in the rear end is not a bad thing. Not to mention the fact you have a .66:1 6th gear allowing nice low cruising rpm with even a low gear in the rear. Stock tires ( around 32" on these gm's) even with 4.10's in the back will be around the 2 grand mark at 70 mph...... It's a very nice combo to have.

 

Toytota I think got it the best with it's 6 speed combo and the 4.30's in the rear.... Overall gearing in first gear is roughly the same between a 3.42 GM and Toyota because the of the Yota's reasonable 3.33 first gear..... and then after that big gap to second in the GM 6 speeds it's all over for any equality between the two.

 

I would much rather have the large gear ( number wise) a fixed position value available in any gear selection than soley betting the farm on first gear in your transmission which is just plain stupid.

[zibzer]

I've been following this post and what I would really like to know is the ratios of the 6 speed and the ratios of the 4 speed to make a better conclusion.

[2005LT]

You have to take into account the transmission gear ratios, diff ratios, and tire size to accurately reflect what kind of mechanical advantage you are going to get.

 

I made a spreadsheet a few years back with the different gear ratios from the 4L60, 4L80 and 6L80 before I got my new truck. I wanted a tool to help me predict what RPM I would be at on the highway. Turns out it's pretty close. With my 265 tires, 6L80 with 3.73 gears I do turn right about 2000 RPM at 120 km/h (74 mph).

[MikeNH]

^

 

Dang! Someone knows their Excel code! That is a pretty nice setup you did.

[rfh1030]

I have 3.42 and the 6 speed. Overall it's no too bad. City driving is definitely hurt with these gears, highway is not to shabby. I pulled 6,000 lbs of dirt with my truck in the summer and while the truck handled it well, I could definitely tell the truck would much rather have 4.10s. I will be swapping mine out eventually for towing and because I do mostly city driving.

 

3.08 is a big hell no unless you drive highway a lot. I was looking at a Sierra z71 in red and loved it, but then found out it had 3.08 gears. Between city driving and taking my truck off road and could not get over having that gear ratio.

 

If you do not want to spend the money for aftermarket 3.73's or 4.10's then go for the 3.42.

 

I went from 3.31 gears on a Mustang to 4.10's and gained a few mpg city while still driving it hard. I only lost about 1 or 2 mpg highway at 80mph. Plus it made driving the car a ton of fun!