I took the car to dealer, a technician took the car for test drive with his driving style the thud could not be herd or was minimal. He drove it on flat road for about 2-3 kms and shifted gears smoothly. He suggested that I should start throttle simultaneously while engaging the clutch, with this I could reduce the thud to minimal, but driving winding up hill still caused the jerk. Should I simply try replacing the dual mass fly wheel? Or is this related to some other issue.

P.S: Transmission engages smoothly when standing still, but there is issue with reverse gear not engaging 7 out of 10 times, unless I shift to 5 th or some other gear for couple of times(for which I have been suggested to replace the link rod).

Thank You