Flywheel/clutch technological "improvement" is apparently born from the boredom of engineers, one might think? If something fairly simple has proven to work well over long periods of time, some bozo will try to change it.
We once had a '94 GMC Sonoma 4x4 with a five speed manual tranny. The tranny self destructed "at speed" when she was borin' down an Interstate in VA, locking the rear wheels momentarily and almost causing her to get run over by a semi.
Local dealer installed a new tranny (still under warranty), never did a thing to the clutch assembly, which was chattery/jumpy afterwards. Got it home, took it to the dealer she bought it from new.
They had the flywheel resurfaced, installed new clutch kit including throwout bearing and "improved" clutch fork. When ya let the clutch out, it grabbed ahold about an inch from the floor and the truck took a "great leap forward".
A mechanic bud that had the current GM shop manual, showed me the section on 4.3L V6 clutches, in which it noted that the flywheel could not be machined, needed replaced if burnt or scored. So back it went for a new flywheel, clutch kit, etc.
IIRC, the flyhweel face where it mated to the pressure plate, was of a slight cone shape design, instead of being flat? It was never right aftewards, as the clutch continued to be noisy and after awhile, got grabby again. The clutch pedal actually shook every time ya used the clutch.
My theory: When the tranny locked up and screwed up the clutch/pressure plate, it also bent the end of the crankshaft enough to make everything wobble a bit.
