I am hoping someone can help me out.

I have a 1992 Mustang with an automatic transmission. I just replaced the engine and after getting everything hooked up I took it out for a drive and the damn thing wont shift into overdrive. All the other gears shift smoothly and on time. There are no rough shifs but when I get up to where overdrive should kick in it dont **** up. Driving at 55 mph the RPM's are around 4000.

Before I replaced the engine the transmission was operating just fine which tells me its something rather easy to fix like an adjustment to the linkage or the kickdown. At the most maybe a stuck 3-4 shift valve or a band adjustment inside the transmission but before I drop the pan and get into the inside of the tranny I was hoping somebody may have had this problem and could give me some help.