I experienced exactly the same thing. It's the clutch release bearing. Lalakas ng lalakas tunog niyan. Tapos unt-unti, magkakaroon na ng shudder. Finally, one day your clutch just won't release when you change gear. You can still shift because you can still depress the clutch. But when you lift your foot from the pedal, hindi sasama pabalik. You have to pump it up and down to make it release. At pag nag release, bigla yung jolt.

Better have it checked now before it damages your pressure plate. Yung sa akin kasi okay pa sana yung pressure plate at saka kapal pa ng clutch disk. Pero yung gitna ng pressure plate na tumatama doon sa bearing napudpod kasi ayaw na nga sumama paikot noong bearing.

Most likely cause niyan is water that seeped into your bell housing. Yung sa akin kasi ilang beses na nagri-river crossing.