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Discussion Starter · #1 ·
Looking to put a 5" lift in my truck and get a set of 35" tires. Currently have upper and lower struck spacers in the front and a block kit in the rear along with a 1.5" body lift. My tires are 34.4"x 11.4" currently and I'm going to upgrade to the 35s. Truck has 3.08 gears and I'm looking to either get 3.73 or 4.10 (opinions welcome), however the head tech at the Chevy dealer I bought my truck from said the computer may not allow it to work Bc there isn't a program out there from gm for that gear size so the truck may not work right after the gears are installed and that it may cost $2000-$3000 by the time they are installed with no guarantee the truck will work after. I'm not taking that as a answer Bc I have a hard time believing no body out there has changed gears in these. I have a diablo trinity programmer and wasn't sure if I swapped the gears and set the new gear ratio in the programmer if it will work so does my computer or anything in the truck need to be flashed?
 

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What is the issue that makes you think you will want to regear with the 35's? Is there an issue with your current 34.4" tires? If not, I doubt that addition of 0.6" of diameter or 0.3" of radius will cause an issue.
 

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Discussion Starter · #3 ·
After doing more research I found that the front carrier can only take as much as 3.42 gears so I guess I need to know if I will notice a good difference from the lack if power I have now and should it be easy for the dealership to reflash my computer to the 3.42 gears since Chevys come with them anyway?
 

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Discussion Starter · #4 ·
Yeah the little bit of driving I do on the highway and the occasional 1500 mile trip down south it's constantly shifting from 6th to 5th and back to 6th again. Also it has no balls when you push the pedal to the floor from a dead stop until it gets to a few thousand rpms. Mainly just want to help the tranny out by not having it shift so much while cruising on the highway
 

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Can the carrier be swapped to one from a truck equiped with 3.73's or higher? for 35" tires the best mix of highway and around town driving will really be 4.10 or 4.56 gears. At least that was my understanding a few years back when i was looking to regear on my 2002.

I think though with the addition of a 6 speed trans, you could probably get away with 3.73's or 4.10's.

And as far as recalibrating your speedo. You are probably going to need a custom tune. I dont know if dealerships will do it.
 

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Discussion Starter · #7 ·
I have the diablo trinity programmer to recall rate the speedo but when I set the truck back to stock if I take the programmer out it's going to think there are 3.08 gears in it still and not run right. I'm have the dealership see if Chevy will warrenty the truck if I just change them to 3.42 since some silverados already come equipped with that gear
 

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I can't imagine they use a different differential housing for the 1500's that come with factory 3.73's. I know my 2008 has 3.73's.
 

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YG GM8.5-456: Yukon Ring & Pinion for GM 8.5" & 8.6", 4.56 Ratio = $185.00
YG GM8.25-456R: Yukon Ring & Pinion for GM 8.25" Reverse Rotation, 4.56 Ratio = $210.00
YK GM8.6-B: Yukon Master Overhaul Kit for GM 8.6", '09 & Newer = $165.00
YK GM8.25IFS-B: Yukon Master Overhaul Kit for GM 8.25" IFS, '09 & Newer = $185.00
YC G26018131: Yukon Carrier Case for GM 8.25" IFS = $155.00
PA Sales Tax = $54.00
Shipping = $40.00
Total = $994.00

Thats a quote from Daves Offroad supply who is a member on this forum also. Thats changing from 3.08 to 4.56. New front carrier IS needed and makes it almost impossible to do yourself being you need some equipment to realign. The rear i would attempt myself but no way on the front.

You then need to have someone install all this and have truck reprogramed.
 

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Discussion Starter · #11 ·
Damn, I'll have to do some thinking. I def wouldn't go above 4.10 gears but I may just see what the dealer says tomorrow after they talk to gm about keeping the warrenty on my truck if I go to the 3.42 gears
 

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4.10 gears would give you same ratio running 35's as the 3.08 did with stock tires. To me thats still gutless unless you live in Kansas and never see hills. When i finally do mine i will be doing the 4.56 and that gives same ratio as 3.73's do on stock tire size.
 

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Well, my part will halp lower that price a lot, if you still want to do the 3.73's. You can probably put it in yourself, as it is just a simple remove and install. As stated before, you can then sell the one you take out and recover some money.
 
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