Other things that can lead to clutch chatter are, worn bushings on the
clutch fork, the clutch fork fingers (where they contact the throwout
bearing) wearing flat spots, one finger of the clutch fork wearing more
than the other thereby putting unequal pressure on the throwout bearing,
and bad motor and/or transmission mounts.

That said, I got rid of my clutch chatter (shudder upon starting off) by
carefully rounding off the clutch fingers with a file and making sure
they were of the same thickness.  As they say, though ... YMMV

Mike

Walter Houle wrote:
> I have lived with this problem for years and have always wondered why.
> I had a factory rebuilt motor and a new clutch installed by a local shop
> and it chattered immediately. It occured in reverse under a light load
> such as backing uphill, or in 1st under heavy load only. The shop replaced
> the clutch disk & pressure plate with new parts twice, but the problem
> persisted. I had so many problems with the first shop that I finally gave
> up in disgust. Later on, a different shop replaced the slave cylinder, but
> there was no improvement. I got fustrated with the whole thing and have
> learned to live with it. If I baby the clutch I can avoid the chattering
> about 80% of the time.
>
> Walter
> 85 Vanagoon 1.9
>