speedo is way off and tranny problems

Please HELP!!! My cars speedometer is way off. When i drive my car it says that im doing a 100mph but when in reality im doing about 55 or 60! But when it gets to 125mph the damn thing drops into "N" and wont do anything till the speedo runs back under 125mph. I have changed the in/output sensors on the tranny, and still no change. I spoke to a friend and he said it might be the tcm? then another said that all the drivetrain is controlled by the "ABS". If yall can help me get back home in 2 days i will give you a "Free" 3 night stay at any Motel 8, Red Foof Inn, or Holidays Inn any where in the USA.!!! I am the area manager and You have my word.

Well, Im sorry I cant help you. I've never heard of a single car doing that. Do you own the convertible? My Speedo(99 sebring convert) only goes up to 120. The only thing I could suggest would be to have a computer plugged in to see if there are any errors.