While driving home after auto zone read my check engine light code ( it was speed sensor module which turned off after they checked it) and my shifter started acting up, not going into gears. When it would go into gear, it wouldn't go past 40. And now the end result is stuck in neutral. I can freely move around the shifter with car in and off with and without the clutch. But nothing happened. Is it the master or slave cylinder or the linkage?