My 2003 LeSabre is due for a power steering change/flush (hit the 100,000 mile mark). Curious if it is okay to use Blain's Farm & Fleet brand Power Steering Fluid? The manual and Hayne's manual are not too helpful (both state to use "GM Power Steering Fluid or equivalent"???). I have used ATF fluid in other cars power steering systems (Toyotas mostly).