I was speaking with one of my long-time ZF tech support contacts in Chicago earlier this morning regarding the ZF 6HP26 Adaptations Drive Cycle procedure's potential effectiveness on our aging XK8s and XKRs. He was aware that Ford factory-filled their 2005 to 2008 Lincoln Navigator 6HP26 units with Mercon SP and essentially acknowledged that the only difference between Mercon SP and LifeGuard6 is the color (red vs. amber). Always good to get confirmation on alternate product viability right from the horse's mouth....