If it popped in gear when in neutral, then the linkage is miss adjusted or bent. The linkage is directly connected to the manual valve. Unless the manual valve is in a drive position the electronic valves (controlled by the range sensor and PCM) can not activate the clutches and servos.
Jumping in and out of gear can also be caused by a bad range sensor or low line pressure.
My advice is to change the range sensor and in the process check the linkage for proper operation. Then if it still broke, check the line pressure. Save the fluid change and flushing for latter. It wonâ??t fix your problem.
jeff
