I understand that the 2021+ GM SUVs have an independent rear suspension, however, it still uses a rear differential and there must be a ring gear diameter measurement for that rear differential regardless of whether it is IRS or live axle.None of the above. It's an independent rear suspension so it uses a different differential than past generations or the pickups. That said, I note that the 5.3 uses a different GM part number for the rear diff than the 6.2 and 3.0 do.
2021 Suburban 1500 3.23 Locking Rear Carrier 1142987 | eBay
6.2L REAR DIFF 3.23 LOCKING G86/GU5. No Grade - A part that has not yet been graded. C Grade - The third level quality part. B Grade - The second level quality part. It is of average miles and normal condition for its age.www.ebay.com