Did you use the right Transmission Fluid or did you forget to maintain your transmission otherwise, your gears are broken and needed to be replaced.. chances are you need a new transmission.
Clutch needs adjustment/replacement Synchonizers worn?
Most likely the clutch-look at disc surface.
if its an automatic change fluid filter in transmission!!
As I understand it: Manual: There are a set # of gears (usually 4-6) and you switch between them as required. Automatic: Again a set # of gears (usually 3-5), the transmission switches them automatically, based on current speed and other variables CVT: Instead of having a set # of gears, there is a belt (or chain?) between the only 2 "gears" that exist. Difference being that 1 of those "gears" changes it's circumfrence, giving it an unlimited # of gear ratios. The transmission determines what the appropriate gear ratio should be, based on speed, how hard you press the pedal, load, etc. Hope this helps.
Is it an automatic or manual if it's an automatic you may have a bad u joints and same for manual, as well as synchronizing gears may cause it to be hard to shift. Otherwise i'd say it's your u-joints
the oil heats up in the transmission and the gears slide easier check the transmission oil and think of a possible change of oil
Hard to say, start with the basics-is the fluid full?
nope...think about replacing the tranny. Check salvage yards.
Not hard if you are mechanically inclined. Having a donor vehicle that is the same as your truck but automatic is key. This would give you all the parts, nuts, bolts, brackets, linkage, etc to do the swap.
If you are sitting on any kind of slope, your transmission has tension on it, making it hard to change gears. Pull your car onto a level place then try it should be easier. If not then your transmission is messed up.
Have you ever changed the fluid and filter in the transmission? If not, that's the first thing you should try.
The most common reason for an automobile transmission to shift hard is low transmission fluid. Make sure the transmission fluid is at the appropriate level.