The clear message coming out of these posts is the need to check the oil/grease condition in sealed gearboxes.
The main issue with these boxes seems to be the slipping out of gear - as in the ball-and-spring not acting on a good lever indent; or the poor condition of the dog clutch.
The second issue is revealed by user habits: Changing gear 'on the run' is different from changing gear when the mower is stationary.
The bevel gears seem usable; I'm not sure about the pinion. Engineer Gadge has covered the correct lubricant on ODK.
Please let us know what transpires. ---------------------------------------- Jack
well took the bevel gears and pinion round to the engineering shop and he had a good look at them and reckons they don't need anything done to them he would class it as normal or minimal wear and to give the box a good clean to remove the old grease and then put it back to gether and fill with liquid type grease and it should be fine . he did say it may have been the old grease that caused the problem other than that he could see no obvious problems with the gears or pinion . so I will get new nuts & bolts then put it back together .