I know there are lots of threads about gear selection problems lubrication issues or something much more serious, and a few due to running hot, (the temperature guage was still slap bang in the middle.) but couldn't see any on GT's and most seem to be about 4th gear, mine is with 3rd.
Last night driving back to Swindon from Reading once I got back on the A419 I found that I had trouble selecting First but it would go in but Third was like hitting a bar, it would only go a small way into the gate and wouldn't engage, it then cleared up suddenly after a couple of minutes of me driving slowly and trying 2nd to 3rd and 4th to 3rd albeit the whole gearbox was a bit stiff, seemed fine again this morning.
Admittedly I had been driving down the M4 at speeds fast enough for the wife to have been moaning at me about me still needing to have a driving licence when we got home.
The car is 9 months old with 12k miles and I am the only owner, so know that the levels of abuse teh gearbox has suffered.
Going to contact Whitequay in Reading tomorrow see if they have any ideas but would be interested if anyone else with a GT has had anything similar. Not taking it to the dealer in Swindon, my lack of sense of humour with them is something I have expressed before on this forum and frankly I wouldn't trust them to clean the car let alone go near it with a spanner.