Hi, first post and im a car noob so be gentle!
I have followed this topic with interest and im having the same issues.
I purchased a i30 active, i believe it is the GD model a month ago. Car drove fine when it was cold, but within 5 mins the gears would be hard to change in 1st and 2nd especially, requiring me to force it. I would get a nice crunch when shifting to reverse too.
First Hyundai I bought, and it is a high mileage one, (145,000 miles approx).
Took to mechanic and he ended up changing the clutch (LUK brand) and slave cylinder. No luck. Then I got a new master cylinder and clutch damper from Hyundai after I researched on this forum on what it could be. My mechanic noticed that the old master cylinder was tampered with and the clutch damper was modified (as recommended on the forum). He installed the new damper and master cylinder and car wouldn’t change gears at all. Removed the OEM damper and installed modified one and car was shifting as before. Mechanic is all out of ideas. It’s been bled and reverse bled multiple times. Is there anything else it could be? I mentioned gear linkages or gear oil to mechanic but he wasn’t convinced. Thanks for your help.
