15RS2NV, I did some research on rearend gear changes when I installed 3.73 ratio in my 13LSM. The Manual was a simple ring & pinion bolt in from Yukon Gears that I took to a reliable shop. What I found in my 3.73 ratio project came down to gear selection. Local Chevy dealer says 3.73 is not available from GM. The Chevy parts guy says a ‘13 LS M6 uses same ring & pinion as the LS3 but GM only offers 3.45 or 3.91 ratios. Yukon Gears offers a YG GM3.73-IRS ring & pinion. Here’s the bad news; Your auto probably is not the same rear end & you may need to swap the pumpkin to a manual V6 or SS. They’re available, that’s what I found for my M6 & the info for the auto came up while I was researching. That’s all I got, your newer model might be different.

Rear End Gears 101
 

Planning to build a gen 5 differential. Are all the diff cases the same v6 vs SS ‘10-‘15 (not Zl1)? Are some stronger than others?


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It’s been a while since I’ve been to this forum. Haha. Seems like “A Long Time Ago, In a Galaxy Far, Far Away”.
What I learned & verified is that Gen 5 V-6 Manual trans models have a late version of the 10 Bold rear end ‘with’ limited slip & 3.25 to 1 gears designed for a 4 link suspension. Very Strong & suitable for a V-6 pushing up to 350hp with after market engine mods available. The Gen 5 V8 models ‘may’ have been equipped with a modern 12 bolt rear end that’s stronger than a 10 bolt. I found that where most of the challenges occur is with V6 automatic trans models because they’re not equipped with limited slip, so a simple ring & pinion swap is not going to provide what most of us want like added strength, limited slip & better gearing than the 3.25 to 1. Good luck with your swap or mods. If you have a Gen 5 automatic trans in a V6 you’ll probably find that swapping the entire axle from a standard trans model is the easiest swap method. For regearing you should recognize that stock ring & pinion are 4 cut gears & most after market are 2 cut gears, or so I was told. The regearing might provide better acceleration but expect some gear noise. Make sure to stick with Chevrolet’s recommended synthetic gear oil. The rest of what I probably don’t know about Gen 5 rear ends would, no doubt, fill many large volumes of small print. Pumpkin Carriage.

V6, SS and ZL1 all have different differentials, and unfortunately they are NOT interchangeable. So if you have a V6 and want to upgrade from 3.27 to something other than 3.55, you'll need to get the whole diff from the model that has your desired gears (i.e. ZL1 has 3.91)

:bonk:

@15RS2NV. Cool thing about car guys. We know metal bends, you can cut it & weld it, there are lots of options produced by aftermarket or available in junk yards. Yep, car guys will almost always find a way. We don’t often say something can’t be done because if you like building cars from scratch you probably wouldn’t mind living in an ice cold garage burning $100 bills to keep warm. You can do ‘almost’ anything, all it takes is skill, time & money. These guys on this forum are all car guys & they know what they’re doing & what they tell you is reliable. I’m bowing out as unqualified. Good luck with your car my friend.

The ZL1 does not come with 3.91, thats the 1LE. The ZL1 came with the 3.23 and the 3.73.

I have a full diff from an SS with 3.45 gears with 45k miles that I want to sell, anyone interested? I just had the local Chevy dealer install a new Z28 diff with 3.91 gears. I also have a new rear diff cover with cooler set-up from the Z28 diff (i ended up with an uninstalled second one due to the way I ordered the parts). Both the standard SS diff and the spare Z28 diff cover are for sale.

So I have a 2011 camaro Rs v6 automatic and want to upgrade gear ratio what do I need to do can I just buy ring and pinion and put it in or do I nees to swap out differential and I hear that I can put 3.91 and then I hear I can only put 3.55 in my car so im a little confused on what to do how is the process like a 3.55 ring and pinion would fit in my car just swap it out but if I want bigger gears I would need to swap differential the axels and all hardware or will my oem axels fit to another differential that has lets say 3.91 gears