Extreme clutch shudder

WHAT CAUSES chatter related to motor mounts / suspension? (and add body mounts in "other" platforms)

When something like a driver side mount is loose, slipping the clutch causes the engine to rise up more than it should. At some point that movement affects the clutch linkage and changed the effective position of the clutch linkage. The "system" reaches that magic point and sort of oscillates. The clutch starts to engage, the engine rises, the clutch linkage changes, and releases the clutch, the engine falls back down. As it falls, the linkage changes position and once again causes the clutch to engage......and round and round we go.

Old friend of mine, --now gone---had a BEAUTIFUL Ford 1/2 ton stick This was a late 70's truck, "just like new" in the early 90's. New clutch, worked terrible. I TOLD him what to check (to have checked), it turns out the "transmission shop" had their head up their ***. A loose/ missing body mount between cab and chassis......simple......took him over a year to get it fixed.

Loose clutch Z bar bracket, loose/ missing bushings, cracked Z bar, bent/ cracked fork, on and on, you simply have to check it all.

And once again don't forget rear suspension.