Self-healing gearbox?

[Galveston]

My bog-standard Clio 172 Cup has a hard life sprinting and hillclimbing. On the way home after an event at Curborough in August 5th gear was very crunchy (bit weird because Curborough only uses 1st/2nd/3rd gears). I changed the gearbox oil as a precaution (made no difference), and continued to use the car for another 5 or 6 events before the end of the season. 5th remained very crunchy on the commutes.

The car hadn't been used since October, however its done ~150 miles yesterday and today and the 5th gear crunch has gone. Selecting 5th is as slick as it's ever been. I've already sourced myself a rebuilt 'box which will be fitted later this winter regardless (1st and 2nd are also a bit whiny), but I'm curious to understand what might've happened. Any ideas?

Cheers.

[227bhp]

The gearbox pixies.

[NotBenny]

Complete stab in the dark, but if other gears aren’t the healthiest they could be, them potentially you had some debris that had got itself in the way of selecting 5th, which has subsequently shifted.

[Galveston]

227bhp said:

The gearbox pixies.

Thought so.

[anonymous-user]

Up on Autotrader it goes before the crunch comes back, one careful lady owner who used it to go to church

[DJP]

NotBenny said:

Complete stab in the dark, but if other gears aren’t the healthiest they could be, them potentially you had some debris that had got itself in the way of selecting 5th, which has subsequently shifted.

That.

Or crap on the linkage now dislodged.