The type of issue that happens every once in a while, not systematically (apparently) so it is hard to pin point the cause.

Well, not systematically “apparently”: Apparently, in fact, it looks like it only happens after reaching some fairly high speed – today was 110 mph (I just floored it for a few seconds and oooops!)

Then I can’t shift the gears anymore. As I downshifted to help slow down, I was able to disengage the 4th gear but not to engage any other gear, not even the 4th gear back. Not the first time it happens.

As I had enough speed built, I was able to get off at the next ramp and stop on restaurant’s parking.

Impossible to engage any gear at idle either. I had to shut the engine down. Then I could shift gears at will, with the engine stopped. Start the engine: Can’t engage any gear. Shut it down and gearbox seems to work fine. Next things, I start the engine with the 1st gear engaged – and the clutch fully depressed, of course. While moving the car in 1st gear, I was able to shift to 2nd gear, then to 3rd, etc. Gearbox went back to normal operation.

As this is not the first time this happens, I expect it to happen again. I may not be that lucky next time and be able to drive back home.

Any clue as to what exactly I should look at?

 

Your clutches going badd. The disk is spreading so that it doesn't completely disengage when you step on the clutch. Either that or else it's just a very badly adjusted, but adjustment doesn't usually change unless a part changes.

 

I agree. Adjust the linkage

 

Check the level of the gear oil.

 

Check the fluid level in the clutch master cylinder......

 

Adjust clutch so you have 1" of free play. Use finger pressure on the pedal pad and a tape measure. You might find yours is more than that. Need to be sure there is no lost motion in the linkage other than the 1" free play.

If the adjustment is good but it still fights you, the clutch assembly is suspect. Clutch may have slipped too much and overheated causing warpage in the disk or pressure plate. The warped parts never get to release fully and the shifting becomes problematic. That requires replacement of the clutch assembly.

 

C3's don't have hydraulic clutch mechanism (unless modified).

 

I thought the same...clutch master Cylinder? Say what? Jeezzzzzz...........

 

I've seen the oil issue too.

Consider rev matching when it occurs. This eliminates the need for the clutch when the car is moving and will tell you whether it is the clutch or the transmission.

 

i had the same thing happen once in my 6 speed the engine was real hot and I was winding it out. I pulled over sat for a few minutes went through the gears and all was well again

never happened again

maybe the clutch is on the way out and the heat put it over the edge

 

My apologies. This thread showed up in the C4 forum. I didn't realize the subject was a C3.