Gears

[skyhighchevyZ71]

I have a 00' Silverado Z71 5.3L and i was told that it has the 3.73 gears i have a 6" fab tech lift and 35" pro comp tires still has great pick up and passing power but should i go to 4.56 or 4.88 gears for muddin

[Stevens03]

You could go either way really, but 4.56's would work just fine. If your looking for most bang for the buck, then 4.88's will do the job, they just aren't as strong of a gear as 4.56's would due to the amount of the teeth. They make a girdle for it, but if you wheel hard, then I'd consider 4.56's for your 10 bolt rear end. If you were willing to swap out a 14 bolt, then hands down 4.88's

[jasprath]

skyhighchevyz71- I just bought an 08' Silverado with 3.73 gears and its stock but I'm wanting to lift it 6" and put 35's on it as well. I don't want to regear so what kind of gas mileage are you getting with your stock gears and the lift with tires? Get back to me quickly please, I want to purchase my stuff asap!

[brad519]

skyhighchevyz71- I just bought an 08' Silverado with 3.73 gears and its stock but I'm wanting to lift it 6" and put 35's on it as well. I don't want to regear so what kind of gas mileage are you getting with your stock gears and the lift with tires? Get back to me quickly please, I want to purchase my stuff asap!

I don't remember what mileage I was getting with 3.73 gears and 35's but I don't think the 4.88 gears really helped out with the mpg.

Check with Matt aka Blackout007 he's got 35's and I believe he's still running stock 3.73 gears.

[stlavsa]

skyhighchevyz71- I just bought an 08' Silverado with 3.73 gears and its stock but I'm wanting to lift it 6" and put 35's on it as well. I don't want to regear so what kind of gas mileage are you getting with your stock gears and the lift with tires? Get back to me quickly please, I want to purchase my stuff asap!

I don't remember what mileage I was getting with 3.73 gears and 35's but I don't think the 4.88 gears really helped out with the mpg.

Check with Matt aka Blackout007 he's got 35's and I believe he's still running stock 3.73 gears.

 

 

Get a tune and do the servos first that should help with the driveability and tranny abuse..

[Georgebaumann]

skyhighchevyz71- I just bought an 08' Silverado with 3.73 gears and its stock but I'm wanting to lift it 6" and put 35's on it as well. I don't want to regear so what kind of gas mileage are you getting with your stock gears and the lift with tires? Get back to me quickly please, I want to purchase my stuff asap!

 

 

im gettin about 15mpg with the 35s and a 3in bl and 2in sl and stock gears

[blackout07]

12 if im good.

[jasprath]

So Matt, you have the stock 3.73 gears in your truck? And do you have 35 or 33's?

[brad519]

So Matt, you have the stock 3.73 gears in your truck? And do you have 35 or 33's?

 

He's got 35" tires 325/60/20.

 

 

Not positive but I believe he is running 3.73 gears.

 

I'm sure he will pop back in and answer though

[ruggedlife]

im getting between 11-12 with 35s and 3.73s on my 09 silverado with the 5.3 and 4speed trans... but tomorrow she goes in for 4.88s WAHOOOOOOOOOOOOOOOOOOOOO any advice for break in??

[jasprath]

I'm getting the 6" BDS lift and 35's, keeping the stock 3.73's. If I get a superchip tuner, will that help my mpg?

[Matt_]

When I had 35s on my 5.3L, which was a HIGHWAY DRIVEN daily driver, i was lucky to see 12mpg with 4.10s.

 

When i put in my 4.88s, I was getting an easy 14mpg.... and the truck was finally quicker off the line than a 27 speed huffy again.

 

 

Either 4.56s or 4.88s would work. I'd go 4.88s though. There's really no realistic "negative". You're more likely to break an axle shaft than shear teeth off the ring gear unless you buy a really cheap set or your pinion depth isn't set up properly. There are even guys running 5.13s and 38" tires on their 10 bolts.... I've yet to see a case where the "gears" themselves were the point of failure.

[jasprath]

So Matt, are you saying that 3.73 gears simply wouldn't work. I want to regear but have heard about all these sensor lights appearing on the truck. And trust me, I have done all my research, that's why I am hesitant. I trust you though as many people on here have said you are the one to go to.

[Matt_]

3.37 gears with the 5.3L and 4L60E is just an all around bad idea with 35s.

 

The truck will be gutless and the trans will hate you.

 

It's also a double edged sword since you're operating well below the power range of the engine and adding stress on the trans at the same time due to decreased mechanical advantage from the gears.

 

People try to solve the "lack of power" issue by adding performance mods to the engine... that's great and all but now you're just putting even more stress on the trans. Thus, a good way to kill it quicker.

 

Properly gearing your truck has two MAJOR benefits:

1) Gets your engine operating around the power band again, thereby improving performance.

2) Increases the mechanical advantage of the powertrain vs the tires, thereby decreasing stress and improving performance.

 

IMO (and here's where some personal preference starts to kick in), anything below 4.56s with 35s on your engine/trans combo is a waste and the truck is going to struggle.

 

Hell, with 4.10s and 35s my truck had trouble pulling around an EMPTY 16' landscape trailer. With my 4.88s I got better gas mileage on my daily highway commute, and was able to tow/haul my trailer with 2 quads, coolers, etc, and fill my bed with firewood, all without an issue through the catskills for our yearly camping trip. My truck was finally a truck again

[ruggedlife]

MRI tech, no i have a superchips with my 35s and it didnt do dick for MPG still waiting for my gear install the guy who does them had a family emergancy, oh well shit happens. id rather have him do it than some random guy i dont know or trust. with my 35s, 3.73s. 5.3 and driving normal to slightly aggresive i get around 11-12 mpg in city.... and when i load my atv in the bed its just a joke