Bearing in the end of the crankshaft, should be changed when clutch is changed as these bearings (at least in the older engines)are known to fail and allow excessive movement of the gearbox shaft/clutch vibration. Earlier engines have a 21mm OD needle roller bearing with a built in oil seal (oil seal is on end nearest clutch). Ford part is 1596468 or 82ET7600DA. Available on next day delivery from www.bearingkits.co.uk tel 01279793631. £7.99 + £1.50 P&P.
(Later engines may have larger, sealed unit, bearing)
Will be added to parts list.