After pulling the transmission to fix the starter ring gear I decided to replace the rear main seal and the clutch. Not that they were bad it's just that it was the best opportunity. However after stuggling for a couple of hours to refit the transmission I discovered that the new clutch plate lead in (the chamfered edge on the clutch plate that the transmission splines start in) was too tight and had some burrs on it! Althougth the clutch alignment tool fit the clearance was such that unless you aligned the transmission PERFECTLY it would not fit up. This is a very hard thing to do when lying on your back under the car. I had to take the clutch disk and hand file the lead in until it slid on the transmission splines easily. Then I could re-fit the transmission. Since I had removed and replaced this transmission a couple of times before without a hitch it hadn't occured to trial fit the new parts.