Hello GM Forum. Im new to this and need a little help.

[jaelmore12]

Once again I'm kind of new to this, not new to trucks, but just all the aftermarket things. So my question Is about my 2013 Silverado LS crew cab. It has the V8 4.8 4-Speed, 2-wheel drive w/over-drive transmission. It currently has a 5" Rough Country Suspension Lift with 33"X12.5" tires. When I asked the shop about re-gearing the rear he said it was not necessary as because it wasn't a big difference from my stock tires to the new ones. Now I'm wanting to add a 3" body lift and upgrade to 35"X12.5" tires. Will I need to re-gear the rear and if so, like I said I'm new to this, so there will not be any reason to do anything to the front since its not a 4-wheel drive correct. I don't use it for off-roading or mudding or anything like that. She is my daily driver and I just really enjoy lifted trucks. During the week she runs easy to and from work which might be about 8 miles round trip and kept under 40mph, weekends I go into town and usually hit around 75mph on the interstate and she settles about 2300rpm. Any help from anybody would be greatly appreciated and definitely taken into consideration when making any new decisions to my truck. Thank you all.

[txab]

Welcome

[Tattooo]

Welcome to the forum & nice truck !

[jaelmore12]

thanks Tattoo.

[Stevens03]

Optimum gear for 35" tires is 4.56's. That will yield the best mileage/torque. 4.10's if you want the best mileage. Personally since you've got the 4.8L, I'd do the 4.56's. Once done, you'll need a programmer to adjust for the gear swap and the larger tires.

[jaelmore12]

Stevens14 thanks for the info and just to clarify, the truck being a 2-wheel drive, I have nothing to do with re-gearing up front right, simply just the rear.

[Tattooo]

Your welcome

[Stevens03]

Stevens14 thanks for the info and just to clarify, the truck being a 2-wheel drive, I have nothing to do with re-gearing up front right, simply just the rear.

 

Yes, 4x2 will only have 1 set of gears to change. After that you'll need some sort of tune to correct the computer. Cost should be between $500-$1000 depending on shop. That would be gear set, master rebuild kit and labor.

[jaelmore12]

 

Yes, 4x2 will only have 1 set of gears to change. After that you'll need some sort of tune to correct the computer. Cost should be between $500-$1000 depending on shop. That would be gear set, master rebuild kit and labor.

awesome thanks for all the help Stevens14. I will definitely start looking into those gears.

awesome thanks for all the help Stevens14. I will definitely start looking into those gears.

and start looking into a programmer or take it to a shop to get tuned.

[Stevens03]

Blackbear is one of the best. He's tuned 3 of my previous trucks.

[99silveradoz71]

Howdy.

[jaelmore12]

Howdy.

Hello there. Glad to be a part of a great forum.

 

Sent from my XT1526 using Tapatalk

[jaelmore12]

Great looking truck! Thanks for joining

 

Tony

thanks 1ATony

[jaelmore12]

alright folks so if you have been reading you got an idea of my issue. ive been doing somw research on gears. i have found so many different gears on different websites. im not entirely sure what all i need. some websites have complete rebuilds and somejust have gears. for example Sierra Gear (http://www.sierragear.com/ring-and-pinion-gear-sets-gm/) that i found has ring and pinion gear sets and 4Wheel parts (http://www.4wheelparts.com/eSearch.aspx?N=1z140frZ7&Ntk=primary&Ntt=4.56+gers) has simply gears. now as i said i have no idea what all i need. and i see all kinds of differenst sizes like 9.5" and 7.5" what is all that, and how do i choose the right product for what i am looking for. and another question can i replace the gears before bigger tires or does it need to be done all at once. again thank you for all te help.

[Doug_Scott]

You can change gears at any time. Same for the tires. I find it hard to believe that you are running 33 inch tall tires, with stock gearing (stock gear on a 4.8 2wd is 3.23) and turning 2300 rpm at 75mph. My truck with the 4.8, stock 31 inch tires, and 4.10 gears runs about 2300 rpm at 75 mph. With the stock 3.23 gears it ran about 1800 rpm at 75mph. Running 33 inch tires at 75mph is about 1700rpm. Running 2300rpm at 75 mph would be correct if you were in 3rd gear though. You may find your truck is not staying in 4th gear due to speed and amount of power available.

 

Running 4.10 gears with 35 inch tires is not far off of what the 3.23 gears and 31 inch tires run speed wise. If you are happy with throttle response when you got the truck, then 4.10 gears and 35 inch tires would be closest match. It also is more friendly with 33 inch tires should you decide to return to shorter tires.

 

One of the main reasons I went with the 4.10 gears in the first 3 months of ownership was the way the truck drove with the small engine, and the 3.23 gears. The 4.10 gears made it much nicer to drive around town which is what I mostly drive.

 

When I had the gears changed, I took the truck to a shop that I had been dealing with when I was a mechanic. Dropped the truck off, told him what gear ratio I wanted, and picked the truck up later in the day. He supplied all parts, and is my one stop for any warranty issues with the gears. Personally, I would not buy parts myself for this, it is far too easy to get the wrong parts, either by your fault or your suppliers, and it will end up costing you more because the guy doing the work is not responsible for your wrong parts.

 

I also found out that the dealer cannot make the changes necessary to the ECM for the gear change. Any change they need for that type of modification requires them to call GM Techline and get a new bin file for the ECM. Techline will not supply a new bin for a gear swap to correct the speedo. Even had the dealership upper management talk to them, still would not allow the change. BlackBear fixed it when I bought a tune.