It cranks but it won't move

I own a 2004 Thunderbird that just all of a sudden, while pulling into an intersection just quit moving. It cranks and runs, but just barely moves. It is a two seater hard/top soft/top convertible.

Check the level of the transmission fluid or check for a leak according to the owners manual. If you aren’t low on fluid due to a leak, it’s going to be to the shop with it.