Interesting. And I apologize. When you said low i thought u meant 4wheel low. As I said in not great with transmissions but if you can manually shift it thru the gears 1 2 and 3 and just D doesn't work maybe there is an adjustment that could be made prior to condemning the entire transmission as bad. And to be honest most of them our year have high mileage. Mine has about 200k on it. Maybe take it for a second opinion or search around on the web a bit more. Repair shops like that will 9/10 times tell you the entire trans needs a rebuild cuz they cant see whats going on inside and hey who knows, maybe they arent even truly qualified to work on these transmissions. Sorry. Ive had my share of **** experiences with garages. And they're not always competent enough to properly diagnose an issue. If you took it to Ford they have crazy scanners that can read every input and output. I wouldnt jump into a trans swap just yet.