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Ok well for a start, those chunky tyres on the back are a big giveaway that this machine has been used on slippery hills. Those conditions are murder on the transmission in these, plus I see it is the later 16hp, the rover transmission was never really designed for the bigger horsepower.
Have you checked that all the belts are tight? how do the corks look, should be 4-5ish mm thick, (under the seat between the big pulleys.
Now You couldn't pick a harder model to change the drive clutch linings. As said above, changing the corks isn't a hard job, scrape the old ones off and contact cement new ones on. but to do that you will need to remove them. on this model it involves removing the sub frame at the back. which holds the entire rear axle transmission assembly.
If you have subscribed and found the parts list section for rover the 28166 parts/owners manuals suit you're machine.
