The free services for the C8 have changed over time. For the last couple years (including your 2023 C8) you get 2 free oil/filter changes (as you've indicated) plus one free transmission filter/fluid top-up. It's NOT replacing all the transmission fluid; only whatever is lost (not much) when changing the DCT filter. The notice that GM sent to the Canadian dealerships, mentions that transmission filter work being done at the same time as the first oil/filter change. But if you followed that, you'd have to do the transmission change again at 12,000 km (it's 12,000 km and not 12,500 km) and pay for it that second time. So with my dealer, they agreed when doing the first oil/filter change, I could wait until 12,000 km before getting the free DCT filter change. I've got 11,000 km on my 2023 Stingray so I'm about to get the second free oil/filter change (before I park it for the winter) and will get the transmission filter changed out as well, if I reach 12,000 km before parking it.
There are some worried about their C8 transmissions, so they'll do the free DCT filter change early...then again at 12,000 km and pay for the second one. Each to his/her own on that issue.
In the US, their C8's always came with one free oil/filter change and one free DCT filter change. For some reason, Canadian C8's initially got 2 free oil/filter changes (that's it). That was later changed to add the free DCT filter change, for Canadians, and we kept our 2 free oil/filter changes as well.
Look at your 2023 owner's manual, starting at page 305 for maintenance information. Here's a part of it discussing some of the first servicing requirements:
Normal Service Every 12 000 km (7,500 mi). Check engine oil level and oil life percentage. If needed, change engine oil and filter, and reset oil life system. Or when the CHANGE ENGINE OIL SOON message displays, have the engine oil and filter changed within the next 1,000 km (600 mi). If driven under the best conditions, the engine oil life system may not indicate the need for vehicle service for up to a year. The engine oil and filter must be changed at least once a year and the oil life system must be reset. Your trained dealer technician can perform this work. If the engine oil life system is reset accidentally, service the vehicle within 5,000 km (3,000 mi) since the last service. Reset the oil life system when the oil is changed. See Engine Oil Life System 0 248. Service and Maintenance 307. When the REPLACE AT NEXT OIL CHANGE message displays, the engine air filter should be replaced at the next engine oil change. When the REPLACE ENGINE AIR FILTER SOON message displays, the engine air filter should be replaced at the earliest convenience. Reset the engine air filter life system after the engine air filter is replaced. See Engine Air Filter LifeSystem 0 250.. The initial transmission external canister filter change must be performed at 12,000 km (7,500 mi). This service can be complex. See your dealer. Caution The transmission external canister filter must be changed at 12,000 km (7,500 mile) during the break-in period. Failure to replace the external canister filter can cause damage to the transmission and potentially void any warranty.
As the old adage says: "always read the directions" or in this case, your owner's manual. Good luck!
