On 4 occasions over the past month, while driving normally, I've heard a very loud "clunk" and the auto trans in my car drops into third and stays there. On the 3rd occasion - a fault light appeared on the dashboard. Once I cut the engine and then restart it goes away and drives normally until the next time (which happened again tonight). A week ago I took it to dealer, they did diagnostics and replaced a solenoid. Fault codes logged were P0743 and P0760 - they checked valves and connections and it appeared to be ok - until a week and a half later (tonight) when it's happened again. I see in OS forums the odd mention of this - dealer says if the problem doesn't happen when they test drive it, they cant fix it - but it's so intermittent that we can't MAKE it happen.. Any ideas?