Best to get re-builders recommendation on that ... imo 100% synthetic ,stands up to the heat better. brand ? your choice but I like Amsoil or Redline and also note : it a good time to flush the lines and cooling section in the radiator of old stuff before filling up fresh
Valvoline Max life ATF. It is Dexron 6 and 100% synthetic. I use it in my 98 Riviera with 184,000 miles on the original transmission. I use the same fluid in my 70 GS. https://shop.advanceautoparts.com/p...VkYJpCh2B1wOiEAYYAiABEgL3F_D_BwE&gclsrc=aw.ds https://sharena21.springcm.com/Publ...2d889bd3/3fa3136a-09bd-e711-9c12-ac162d889bd1