I put a clutch and throw out bearing in it about 4 months ago. All the sudden driving went to shift from 3rd to 4th and it wouldn’t go. If you turn the car off you can shift it into gears. BUT if you try to turn the car on in gear it just jumps forward. I have had guesses all over the board about what it COULD be. It seems like a very exact problem to me. BUT with that said I have never worked on a car, just drove one.
You appear to have a problem with the clutch release system. Check to make sure that there is jydraulic fluid in the clutch master cylinder reservoir. If the reservoir is up to the minimum line, you may have a failed clutch master cylinder.
Does the clutch feel right i.e. point where pedal resistance becomes noticeable has not moved and the pedal feels okey all the way down? Have a mechanic observe the action of the slave cylinder push rod against the release fork. If the release mechanism is operating okey, then the problem could be something wrong in the clutch itself.
Let is know what you or your mechanic find.
Yes, the clutch feels normal and the slave cylinder is pushing the release fork. When you start the car in neutral the fork vibrates left to right. When it happened there was a noise that sounded as if something “came off”. The car shifts gears when it is off, but once the car is running with WILL NOT shift.
There are a number of things that can happen to the clutch disc that can fustrate disengagement. One of the torsion springs can break or come loose from its restraint. Clutch friction material can come loose and pile up against the pressure plate. On a wild guess, I would assume the latter as a piled up friction would cause the diaphragm fingers to be uneven and vibrate the fork. It looks like the clutch will have to be looked at.
Would That Make The Rest Of These Issues Happen?
Yes it would cause blocking of the 3-4 shift as the synchromesh mechanism will block the shift if there is any RPM difference between the input shaft and the engaging shift collor sleeve. If you matched speed exactly you might be able to slip through but it would be rough on the synchro ring if not done delicately.
The tendency to jump forward when you put the transmission in gear with the engine ‘off’ and start it with the clutch pedal down if the clutch was not releasing.
Have you tried starting by cranking the engine with the transmission in 1st or 2nd. Once the car is rolling push the clutch pedal down and brake to a stop. Does the engine shudder to a stop?
Have you tried putting the transmission in gear 3rd or 4th; pushing the clutch pedal down; engine ‘off’; and having someone rock the car fore and aft to see if you can dislodge what ever is caught in the clutch? This would not be a lasting repair but you might be able to get it to the repair shop with the clutch disengaginp properly.