I've done the typical pan drop, new filter and fluid change at least a dozen times on Fords thru the years. This has never happened, and it's urgent. Drove into the garage, dropped the pan, cleaned the magnet and put on a new filter, replaced the pan, and topped up with about 5q of fluid. (Used Castrol certified MercV) Now it won't go into gear, any gear. Nada. Any ideas? I've never seen anything like it, and am at a loss as to what could've gone wrong on a simple procedure. I did idle it for a few minutes, check the fluid a few times to make sure it's the right level, and it is. Help!