no overdrive. all other drives work. on 1990 Lincoln Town Car

on overdrive what so ever engine just revs. all the other drives work fine

Asked by for the 1990 Lincoln Town Car
It is possible that you will only need a sensor such as TCC. How ever it sounds more like the clutches, or other internal problem. We would only be able to guess here without checking it out. I believe you are going to have to take it in for diag. and repair.