i have 2000 FIAT Siena 1.4el 5 speed manual and its done only 105000km (around 60000 miles) in 23 years ever since we bought it in late 1999 , it has cable operated clutch and sometimes i hear really loud PAT like sound when shifting. Its not like a grinding or crunching or whining noise, there is just a loud PAT like sound. I think it has happened when downshifting from 4 to 3 and when shifting into second from first, so i have a feeling its something to do with clutch maybe? Also the quieter pss sound im talking about kinda sounds like you know when you disconnect the air hose after inflating a football ball or a tire and you hear a pss sound after disconnecting the hose its kinda like that but it also happens when shifting like the PAT sound. Also i first noticed this 2 weeks ago and has only happened 3 times and the gears are all fine the synchros also work fine still and i know the clutch on it is really old i think it still has same clutch from 1999 when my dad first bought the car brand new so could this sound be coming from the clutch?