Matt2013LT

I honestly never got it tuned! I've only ever got the speedometer calibrated, but I've only driven it 10k miles since August 2022 When the lift + tire's were installed! And you are correct, a gear ratio like a 4.10 would probably be more optimal (that option is still on the table) but even the gearing with 3.73's on 35's is even slightly better than 3.08's on 265/70R17's! The 6L80E has a 1st Gear Ratio of 4.03 and a 6th Gear Ratio of 0.67, so I also agree with you that the 6 spd still wouldn't mind the 3.73! The RPM's would also be quite low with the 3.73 according to the gear charts & calculators I tried! I also will get it tuned at the same time as the new gear ratio. I should've got it tuned to begin with, but I for sure will when the gears go in for maximum efficiency.

I totally don't disagree! That would be most optimal for fuel efficiency! But I love a lifted truck! Just my preference though!

I currently have a 2013 Silverado CCSB 5.3 2wd with a 6.5 inch zone lift kit on 2020 Silverado 20 inch RST Wheels mounted on 35 inch trail grapplers! I currently have the crappy factory 3.08 gear ratio. As you can imagine, a truck with 35's with a 3.08 is an absolute dog! Holds gears until 2500 RPM, 6th gear is totally unusable over 60MPH, and 9.5 AVG Fuel Economy. AFM/DOD has been removed from the engine also. When I first bought the truck in July 2021, it was a mostly bone stock 1 owner truck. It had the 17 inch alloys on 265/70r17 Goodyear wranglers on stock suspension. RPM's were relatively low with the 3.08, but of course, mostly stock! Averaging 13.2 MPG I've recently have had to do some long distance driving & the low MPG + price of fuel is costing too much! For anyone that has knowledge on this, do you think it's possible to put a 3.73 gear ratio in with a 6L80E & 35s, and have lower RPM's, or is it best to go for a lower gear ratio like a 4.10+ ?? I'm just trying to get as much fuel efficiency as possible! Any input would be great! Thank you

You bring up a great point! I did not think about the tooth count being different! Will definitely look into that! I did get the wiring for the ABS from the 2015 Donor truck, so I suppose I'll have to see if they match or if I need to retrofit some things! Thank you for the input.

I presently have a 2013 Silverado LT CCSB 2wd 5.3 With a 6L80. It has a 10 Bolt rear end (GU4) with the sad 3.08 Axle ratio. What's really bad is that I am currently running 35x12.50R20 Nitto Trail Grapplers on 20 inch 2020 Silverado RST wheels with that very high gear ratio. 6th gear is basically unused at this point even doing 60 on a hwy. From what I understand, the 12 Bolt rear ends from the 2014-19 Silverado's are stronger than the ones on 2007-13s! Well a nearby junkman had a 2015 Silverado 5.3 Double Cab + 6 3/4 Bed. It was a 2wd WT Trim level, White, very bare bones pickup, that had also been in a front end collision. The scrapyard owner had the axle for a low price, so I hopped on it. I currently have the axle in the process of tearing it down. My goal with the axle is to clean it up, get it powder coated red to match the truck, and swap a 4.10 axle ratio into the 2015 Silverado 12 Bolt rear axle. From what I understand the 12 Bolt can handle more power, weight, and is stronger than the 10 bolt. And the 12 Bolt I picked has disc brakes because it's from the 2015 Model Year. For anyone that is still reading & has knowledge about this, is there any big modification I have to do? The 10 Bolt & 12 Bolt Axles both look as if the shock mounts & where the leaf springs rest, are in the same positions for mounting! I heard I might have to swap brake master cylinders if I do a disc brake conversion because the 2013 Axle has drums, while the 2015 Axle has discs. Any advice anyone can give me would be appreciated! Thank you.

IMG_0840.HEIC Honestly, not sure if this is going to help your case but may give you more confidence! I have a 2013 Silverado CCSB Z71 2wd, it too has the wimpy 3.08 in the back! Even worse I have a 6.5in lift and 35 inch Nitto Trail Grapplers! I have hauled a 4,000lb trailer with it before! It can do it, but it'll definitely like to hold gears! Even for stock size wheels, the 3.08 still lacks in my opinion! If you really like the truck and you have the money, you could regear it to something more optimal like a 3.73+ if ur towing!

I recently bought a red 2013 Chevy Silverado, I love the truck, but theres some things I wanna change on it. My neighbor recently bought a 2020 Silverado RST. He is selling his wheels, they are the gray 20 inch RST rims. I would like to replace the 17 inch alloys anyways. Since I plan on lifting my truck 6.5 inches. Do any of y’all know if a 35x12.50R20 would fit on the 20 inch RST’s?

I know I have a older truck than y'all but I recently bought a Red 2013 Silverado LT CCSB Z71 2wd. My neighbor has a 2020 Silverado RST with the 20 inch Gray RST wheels. He said he'll sell me the rims. I want buy them so I can get off of the ugly stock 17's the truck came with. I want to do something different than everyone else. do any of y'all know if a 35x12.50R20 would fit on the 20 inch RST wheels? I also planning on putting a 6.5 inch superlift on it so I'm not really worried about fitment.