I own a 1941 Ford pickup with a 1987 Lincoln Town Car engine installed in it. The tranny will not shift into 4th gear. It has a Lincoln Versailles rear end. I did not do the build. I assume that the tranny is the 4 speed with auto over drive. Where do I start to fix this problem? I have been reading a bit about the Lincoln Town Cars and it seems that the car had a button to shift it into over-drive. I see no button. The builder installed cruise control. At 65mph, the tach reads 1700 and it seems that the tranny should be shifting to 4th gear. 1-3 seems fine but the tranny does not kick up to 4th. I can hear and feel the tranny moving from 1-2 and 2-3, but nothing free that point. I assume that I should also feel and hear a shift from 3-4. Why is the shift not there? Thanks for your time and suggestions! This truck is driving me crazy!