Reply to "Reverse gear - grinding noise"

Thanks for all that good feedback. Meanwhile I checked the clearance between flywheel and clutch disc. The clearance is well above 0.05" but I found that with the clutch fully disengaged there is still some friction noise between flywheel and clutch disc. I was suspecting that the clutch disc was not freely moving on the gearbox shaft and keeping still a bit of contact with the flywheel. I decided to put brake cleaner into the clutch hoping to wash out deposits from the gear shaft. That worked to certain extend and I can now into reverse without noise provided I had the gearbox stopped before with the first gear. I also realised that I can very easily move the clutch disc with disengaged clutch and the gearbox in neutral which demonstrates that with the red line oil the gearbox moves without much resistance. That means that already a very light contact between clutch disc and flywheel is enough to get the gearshaft moving thus resulting in noise when putting in the reverse gear. It is probably a good idea to go back to the 80W90 gearbox oil.
Brgds
SIG