Transmission Problems are no fun.
Transmissions are designed to go shift when needed, so when they hesitate or refuse to go, there's something wrong. With manual transmission problems, you may notice after shifting into a gear that the car's engine will rev up, but the car won't be accelerate. In this case, a worn out clutch or more serious transmission problem may be occurring. It's also possible for the stick shift to pop out of gear and back into neutral if the shift linkage is out of adjustment. Automatic transmissions have the their own type of problems. When shifting into Park or Drive the vehicle should have a quick response. If your transmission hesitates to go into either one, then it's likely there's an issue with the transmission. Sounds to listen for would include, but not limited to, a whining, humming or even a slight buzzing sound with an automatic transmission. With a manual transmission if you shift gears and hear a clunking sound, then you definitely need to have it checked out. A clunk from under the vehicle could also be from the constant velocity (CV) joints or from the differential.
Manual and automatic transmissions respond differently when your transmission isn't working correctly. With a manual transmission, a common sign of trouble is a grinding when you shift into a new gear. If you hear a grinding sound with the clutch pedal fully depressed, you may have a worn clutch or you may just need to have it adjusted. It's also possible that the shift linkage may need to be adjusted as well. Grinding gears can be caused by a number of different reasons.
With automatic transmissions you'll most likely feel the car stutter or slip
into each gear rather than the smooth almost unnoticeable shift, or the
transmission will almost fell like it jumps into the next gear. Both are signs
that you have a transmission problem. If you notice anything other than a smooth
shift between gears, then you might need to have your automatic transmission
looked at for adjustments or repair. You should also have your vehicle checked
if your check engine light is on. Keeping your Transmission Problems to a
minimum is a great solution!.