Gearbox noise - throwout bearing?

[dizzycap]

My 901 gearbox/clutch has started to make a horrible sort of grinding noise just as I raise the clutch pedal. Must be the throwout bearing?

It is hard to avoid it when starting to reverse. I really have to eeaaasse off or this horrible noise starts. Worst case in these standstill situations I can’t even make it stop by just pressing down on the clutch pedal again. I have to yank it out of gear to make it go quiet.

Also in first gear it is pretty sensitive in the same mannner, but not quite as bad as reverse.

So no issues selecting the gear, but once I let the pedal up the noise starts. Once it has passed no issues coasting or anything.

And this happens on all gears. I can put second third, fourth, fifth gear in without problem, but ever so often I get a short crunch just as I start to let the pedal up.

I was thinking the synchros, but surely they can’t all have gone from good to bad in a few weeks.

Also I can provoke/investigate the noise by pressing and releasing the pedal whilst staying in the same gear. So same gear, still get the noise just as I release the pedal. That would rule out synchros, I think?

So… throwout bearing must be the culprit?

Bad pilot bearing? But that should make a noise more constantly?

Should mention I run Swepco, but have ordered mineral EP90. Don’t think symptoms points to oil though.

[Bruce M]

Throwout bearing is more likely to be noisy when the clutch pedal is down & it’s spinning. Would also be noisy when you are in neutral.

I’d be suspicious of the bearings. As the gears have angled teeth, when you lift the clutch and the forces increase, the gears push sideways towards the bearings at each end of the shafts, as well as pushing the shafts apart.