I have a 2013 SilveradoWT 4.8L and I've been using this synthetic oil "blend" as recommended in the owners manual, but it's no longer available. Can anyone recommend an oil? I have around 44,000 miles on it.

ACDelco 10-9050 5W30DEXOS 1 SB-Q

 

You should be able to use any good brand of full synthetic Dexos 5W30.

 

Hell, I use Amazon Basics full synthetic in my rig. Is made in the same plant as Mobil 1 and in tests ran side by side, you can you tube the info, Amazon Basics was beating Mobil 1.

But any major brand oil should be fine.

 

if it's got the Dexos logo on it, then it's good enough for your truck. GM makes sure of that.