Further to the aftermarket clutch findings

You may remeber I found some conflicting info about the Celica
Alltrac/GT-Four clutch spline sizes according to a few sites quoting Aisin
(OEM) numbers and other aftermarket manufacturers.

Well I eventually got hold of the Aisin cataloge and found all of the
splines are the same size (28.8), but not the size all the aftermarkets
use(29.8), but the smaller of the two I had previously determined were
possible. What, from cursory investigation, appears to have happened is that
aftermarket makers have assumed that the 3S-GTE based cars have the same
spline sizes as the 3S-GE based cars and just a larger friction plate. In
actual fact the GTE has a higher clamp load pressure plate too, and higher
again in later years - so its a whole mish-mash of possible mistakes. It
would, IMO, explain many friction disc failures and noises ive seen on
aftermarket plates and why Toyota clutches hold some mythical position as
"being stock but capable of holding an aweful lot" - its may be because the
aftermarkets are made wrong and so even a "stage 2" fails on a stock car due
to radial play and bad loading of the friction disc. Maybe if they had the
correct spline diams they'd centralise better, and carry the load more
evenly - therefore not shattering, breaking apart at the springs or wearing
oddly.

I'm currently chatting to a couple of aftermarket manufacturers who are
taking the question seriously and looking into it.

J