In the morrning hesatant to shift back up from 3rd to 4th gear.

Im assuming it is a 4 speed transmission and if you are using the "tap shift" which is for performance situations and you wouldnt typically need 4th gear. What speeds are you trying to go into 4th? If you are going too slow it wont upshot because you rpms might drop too low. Will it not go into 4th at highway speeds?

When did you last replace trans filter and fluid? Dirt may be causing shift valve to stick.

you locked it into a specific ratio when you went down hill in 2 nd
it will not upshift until you select drive again

Sounds like you have a manual transmission. The problem as described is more than likely a worn detent on the shift rail. This is a job for a gearbox specialist.

Check the transmission computer

If tranny fluid is clear and at normal level, then the issue is with the transmission - it is getting ready to go sayonara.

Better get that fix before you get stranded.

PROBABLY A BAD SYNCHRO IN THE TRANS. MUST BE A 5 SPEED?

sounds dumb but Have you checked the tranny fluid?

TRY PUTTING SOME LUCAS TRANS ADDITIVE IN IT IT HELPED MY 99 EXPLORER STOP THE SAME PROB

how do know this isn't normal, u make no mention of the engine load when this happens, very vague question, need all the facts about the problem if it is one.