Transmisson will not shift into gear. Going to pass a truck on the highway and it is like the transmisson just shifted into neutral. Will not shift into any gear. Engine runs good and no oil leaks.

most likely one of the transmission shift solenoids.
A little google search and some youtube videos will walk you right through the issue.

sounds pretty normal. what speed do you try out the passing gear? anything above 35-45 mph and it will feel like neutral. Passing gear is actually only 1st gear. When you press down the pedal, it forces the transmisson to shift into low gear.

First off there may be nothing wrong. At highway speed, the trans will shift down to 1st, but you won't feel it. If should feel like neutral. Does it shift normally when your "wide open throttle" from standstill? If it shifts properly in this situation, then your fine, don't worry. How about wide open throttle at say 25mph? how about 35 and 45? anything over that and its gonna feel like neutral. IF your convinced that your passing gear is not working right, it could mean that its out of adjustment, and needs a little more push, more throw, or kinda like adjusting the rod out a little bit further. Adjust your "passing gear linkage" or kickdown as you imply. Second guess would be low on transmisison fluid, filter, and last, the transmissoin control selonoid. Again I suggest its doing just fine, if it shifts down at any speed.

I had trouble with what seemed like a transmission on my ford van. Was told by a master mechanic to disconnect the NEGATIVE battery cable for 5 minutes to reset computer. I did this, it worked & never had another problem with it. Maybe it will work in your situation. Doesn't cost anything to try!:)

The normal issue with a faulty switch is the car will not start in park and-or neutral and the backup lights may not work in reverse.

I have a 92 Crown Vic first and second works fine reverse works fine when it shifts in the third gear it goes to slipping and overdraft can you help me fix this problem thank you

If tranny is manual shift you may have a bearing and or bad gear. Try changing tranny fluid. Check manual for correct fluid may use tranny fluid rather than gear oil. I recommend using Royal Purple fluid or gear oil. This very expensive but will slicken up the shifting and extend bearing and gear life.

ck fluid level,,ck color or smell it to see if it smells burnt,,trans filter could be plug up

this is normal for the transmisson to down shift out of over drive it does this because your engine is running out of power on the up grade. now you shouldnt be alarmed unless it slips out of overdrive on a flat road

It sounds like it is in limp mode, this means that there is a transmission problem. The trans will go into limp mode to protect from further damage. You need to take it to a trans shop to have diagnostic test