davetd wrote:Is a noisy input shaft bearing or final drive with play in it likely to fail or will it just be noisy?
davetd
Dave, it'll go on for a good bit and then fail at the worst possible time. 20 years ago, a Rover SD1 taking us to Heathrow did just this. Rumbled for moths, chose that moment and we nearly missed our flight!
I was speaking to one of our Apprentices today who runs a 205 Junior. he was worried that he changed his gearbox oil at the weekend and found two big ball bearings were attached to the drain plug magnet. His is a bit noisy and he is having difficulty in getting first and second gear now. It's been like that for months upon months

His is a little 954cc 205 so is coping with much less torque than yours. Even if it does go, the fact that the input shaft is also supported by the pilot bearing in the flywheel usually means it'll get you home if you take care and use the clutch as little and carefully as possible.
More worrying in your case is the apparant play in your final drive. This is very likly to fail spectacularly if indeed it is excessive. A bit of apparant backlash in the final drive is pretty normal generally although in rare cases the sun and planet gears decide they've had enough and exit stage-left through the diff housing..
Totallyb agree with getting a recon box. At least you know what you have then.