Holden Barina Gearbox & Transmission Problems

Yes, any competent mechanic can do it, there’s no need to have a Holden dealer do the work.

IT IS possible the clunk will go away. I don't think you're doing damage, but if it's still there when you take it back for the first service, mention it again to your dealer.

While the carmakers will tell you the transmission is filled for life the old timers in the auto business will tell you otherwise. It’s wise to regularly check the transmission fluid, and change it every 20,000-40,000 km depending on the use. You can leave it longer if it’s being used for normal driving, but if it’s towing it should be changed sooner rather than later. The transmission is working fine and it’s got fresh fluid, so there’s no reason to think there’s a problem on the horizon.

Yes, it is worth checking. It could just be leaking and need new seals, but it really depends on the rate of the leak. If it’s leaking at a rapid rate you should be able to see oil on your driveway, if it’s not it might just be that you need to check it once a week and top it up as needed. If you are worried take it to your dealer, or an auto transmission specialist.