what gear for 35's

mossracing47 · March 3, 2005

i own a 99 silverado and recently put a 6" rcd lift on. Now that i have it done and the 35's on it i realize how much power i have lost. with a load the 3.73 is straining. any suggestions for a new gear i have heard 4.56? and how much to purchase and installl front and rear(ball park figure)?

thanks,

Stryker · March 3, 2005

I don't know but am really interested too. I have 3.42 gears with 33" tires and feel it too. I have hear about $300-500 US to purchase the gears. Not clear as to wether it includes labour. Would you do the work yourself or have it done?

Would like to see pics on the lift.

mjgjr72 · March 3, 2005

i put in 4.56's, cost me about 500 for gears, bearings and install kits and fluid, did install myself

teaklejr · March 3, 2005

I have a 1500hd with 35's and put 4:56 gears in it and they are perfect. They seem to be about where the truck was stock as far as the rpms go. I turned about 2400 at 75mph stock and it is the same ow with the 4:56 gears. Hope this helps.

facn8me · March 3, 2005

I'll go to 4.56's when I get the chance. I have 35's

mossracing47 · March 3, 2005

thanks for the help guys, i just joined the other day, how do you post pics?

woyster_00z71 · March 3, 2005

Hey mjgjr72,

How was the install? I have been wanting to go with 4.56's on my Z71 Tahoe with 35's but I can't make myself pay $1000+ in installation charges. The cheapest quote I got so far was $1500 for parts and labor for both front and rear gears. I'm interested in doing the work myself but don't know if it is possible. What all is involved? What tools are needed? I'm a Mechanical Engineer and currently do all my repairs and maintenance so the mechanical working won't be a problem.

Thanks,

B.J.

REDZ-71 · March 3, 2005

If you gona tow, then go with 4.88.

If you are not doing a lot of towing than stick with 4.56

My 99 came with 3.73

I just got it regeared to 4.88 and I'm running 35'' tires.

One thing I noticed after the first test drive is the increase in power and gas milege.

Next thing that happend was my abs and brake light kept coming on every few miles, and of course spidometer/odometer was not working properly.

My solution: Since I had a HPPIII, I chose 33'' for tire size and 4.56 for gear size - that is equivalent to 35'' and 4.88 gear. So that took care of the spidometer/odometer and the brake lights.

Now as far as the costs:

$500 for set of 4.88 gears with master install kits and shipping (Got the youkon gears at Randy's Ring and Pinion)

And $700 to install (The off road shop in dallas did the install)

Originally they wanted a $1000.00 for the front and $350 for the rear, since in order to do the front they have to remove the lift kit (I have pro comp 6" lift) in order to get the front axle of the truck. So lucky me I had a spare front differential (don't ask why and how I got it ) - so I took it in over the counter and they regeared it for $350. Then I vent home and pulled my suspention off and sawamped it my self (took about a day - but I also changed all of my bushings, idler arm and pittman arm and some other things - I didn't have to change this out but I did it anyway since I had everything dissasembled.

I still have my front differential that I took off my truck if anyone wants to buy it.

(it has app. 30000 miles and it has 3.73 gear in it...I'll let it go for $450)

mjgjr72 · March 4, 2005

Hey mjgjr72,

How was the install? I have been wanting to go with 4.56's on my Z71 Tahoe with 35's but I can't make myself pay $1000+ in installation charges. The cheapest quote I got so far was $1500 for parts and labor for both front and rear gears. I'm interested in doing the work myself but don't know if it is possible. What all is involved? What tools are needed? I'm a Mechanical Engineer and currently do all my repairs and maintenance so the mechanical working won't be a problem.

Thanks,

B.J.

<{POST_SNAPBACK}>

i work on cars for a living and have done a few rears and have most of the tools needed. with that said the rear was easy the front was a little hard since it was the first split case diff i have done.

this is not something that i would recommend you do yourself, inless you really want to, there are a few special tools you have to have and a few that just make it alot easier. and a few adjustments that take some time and patiance to get right, if they are not the diff will be noisy and or the gears and bearings will fail.

if you are really interested in doing it it is not that hard, get a manual (a good one, dealer manual would be best) and read up on what is needed and involved, if you can borrow or have access to the tools needed and think it is something you would like to do, go for it.

for most people the cost of renting or getting all the tools and time involved doing the swap and fact that there is no warrenty on the job u do it is just easier and safer to have it done.

vhato · March 4, 2005

I am a HEAVY user of FullSizeChevy.com and I wrote an article on how to do rear gears. I am writing an aritcle right now on the front IFS. I do gears pretty often.

Here is my article over at FSC. Be on the look out for my front IFS article.

It is at the bottom labeled 10/12/14-bolt.... You'll see it.

http://www.fullsizechevy.com/fscu

mossracing47 · March 5, 2005

If you gona tow, then go with 4.88.
If you are not doing a lot of towing than stick with 4.56

My 99 came with 3.73

I just got it regeared to 4.88 and I'm running 35'' tires.

One thing I noticed after the first test drive is the increase in power and gas milege.

Next thing that happend was my abs and brake light kept coming on every few miles, and of course spidometer/odometer was not working properly.

My solution: Since I had a HPPIII, I chose 33'' for tire size and 4.56 for gear size - that is equivalent to 35'' and 4.88 gear. So that took care of the spidometer/odometer and the brake lights.

Now as far as the costs:

$500 for set of 4.88 gears with master install kits and shipping (Got the youkon gears at Randy's Ring and Pinion)

And $700 to install (The off road shop in dallas did the install)

Originally they wanted a $1000.00 for the front and $350 for the rear, since in order to do the front they have to remove the lift kit (I have pro comp 6" lift) in order to get the front axle of the truck. So lucky me I had a spare front differential (don't ask why and how I got it ) - so I took it in over the counter and they regeared it for $350. Then I vent home and pulled my suspention off and sawamped it my self (took about a day - but I also changed all of my bushings, idler arm and pittman arm and some other things - I didn't have to change this out but I did it anyway since I had everything dissasembled.

I still have my front differential that I took off my truck if anyone wants to buy it.

(it has app. 30000 miles and it has 3.73 gear in it...I'll let it go for $450)

<{POST_SNAPBACK}>

With 4.88 what rpm are you at at 75 mph? is the noise noticable with pipes? i do do a lot of towing i will look into it. Hey guys thatnks for all the help

REDZ-71 · March 6, 2005

I think its at 2800rpm, I'll have to double check it next time I'm on a highway. It is noisy, but I'm running the loudest Flowmaster muffler too - "I don't drive it if it aint loud"