On a 1989 zetor 6211 I recently bought I understand gears 4 and 5 are synchronised so unless you double clutch the other gears will grind, when getting used to this they have grinded on me and previously I hadn’t been aware of double clutching so will this harm the gearbox or realistically would it have to be done for many years to cause harm? I find double clutching very hard to work when shifting gears below 4th however it seems to work fine on my Massey 135. Is it just a matter of getting used to double clutching with matching the revs? The clutch pedal is pretty slow on release so lacks that fast spring which makes it slower