I recently bought a 2008 Impala 3.5L. According to the Carfax it was a rental for 8 months before I bought it so I am looking to change and flush the ATF and I want to use Royal Purple. I don't want to give Chevy a reason not to honor the warranty, in needed, so I was looking for documentation (preferably from Chevy) saying that Royal Purple ATF won't affect the warranty. Anyone know of a link or documentation? Thanks.