Ok, here is the background. I have a 2010 Flex EB with 170k on the clock. It has 84k on the long block (melted a piston under extended warranty), and less than 15k on the turbos. It was my wife's car for 5 years. I bought her a new Flex, and I took the old one as my toy. I have installed hot pipes and a Torrie tune about 2k miles ago. I have been going through it replacing bushings, tie rods, etc. I stumbled across the fluid change talks on here and realized my Flex has the original tyranny and PTU fluid. I am planning to put Amsoil in both.
My thoughts were, since it has so many miles on the original fluid, to use valvoline max LV, because it's less than $18/gal at Walmart to drain and fill several times, drive it for a few days and THEN drain and fill twice with Amsoil.
Does this seem like a good idea, or should I just drain and fill with the Amsoil? My thought is to use cheap stuff to clean it out, then switch to my long term more expensive fluid.