[TR] Knocking noise

[Randall]

> I see that TR5 and TR6 boxes are the same as a TR4.

Only early TR6 at best.  There were a lot of incompatible changes during the
TR6 run.  I wound up having to use TR4 gears to put an A-type OD onto a CC
series (IIRC) TR6 gearbox.  Some of the things to look for are on the TRF
website, in the TR6 catalog gearbox section.  The change in dog tooth
pattern is a particular problem, as the mismatched parts will physically fit
but not work right together.  I know someone who spent a year figuring that
one out!

Complete gearsets will interchange, but not necessarily individual pieces.  

The TR6 housings also have thicker flanges, which isn't too serious but
causes issues to be dealt with.  You'll need longer studs on the engine, and
the clutch slave mounting changes.  I shortened the pushrod to make mine
work, but in retrospect it might have been better to pound the cover flat
and move the bracket to the other side.

-- Randall