Ihave a 2005 Crown Victorian and it reverse just fine, but when i come to a stop

NOT SURE WHAT THE FULL QUESTION, BUT GIVE ME A CALL IF YOU HAVE ANY QUESTIONS.

My 2005 is doing the same thing. Drives in reverse fine, but will not catch in drive unless I rev the engine. Turned off O/D and I still have to rev the engine to go forward, but only initially. Then it drives normal unless for some reason you take it out of drive. Then you have to rev the engine to make it catch again.