Yep, Suzy's been strictly fed nothing but Amzoil since about 20k in every orfice that will accept oil, with the exception of the S/C, which uses the GM synth.
I tried Mobil1 one time, when I was drawn to the bargain side of the force...
I noticed more valve noise with that experiment & have never looked back.
I still change my engine oil & filter every 3-4 k, & will let my trans & diffs go an extra 5-10 k past reco'd intervals.
That's what works for me...
And YES...it DOES offer continued protection whilst lazing about in a tub...![]()