I have a 95 Bronco with 5.0 and the overdrive light is flashing and is starting to shift hard. It got a new transmisson about 15,000 miles ago. Any ideas on what would cause this?

 

Recommendation to pull Codes and see what the onboard computer "tells" you. Could be something as simple as an overheated transmission or as complex as a failed solenoid pack in the trans.

KOEO and KOER tests should yield at least some if not all of the information needed to troubleshoot the problem.