Very loud sounds after clutch / flywheel change
 

After a clutch/flywheel/bearing change I have a lot more sounds in 4th to 6th especially it seems, I plan to test swapping the oil to Redline to see if that helps. But starting in first and reversing have very loud sounds and feels very clunky.
I did go for a lightened flywheel, but it's a stock clutch I changed to. I know they had a lot of issues getting the old flywheel off, so I was wondering if they could have forgot something putting it back together in a rush. I'm always happy with their work, but now I don't feel comfortable driving it as I don't know if it's supposed to be like this. It's always been a noisy gearbox and driveline, but this doesn't sound normal.

Videos:

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I would take it back to whomever did the work. The videos don't make it easy to localize the sound or figure out what the problem is, but if it didn't make that noise before, it's a safe bet the the work performed has something to do with it.

It could be anything from low fluid level to poor bearing install, clutch alignment or not tightening that giant nut enough. Some of those are easy fixes, some of those can lead to clutch shrapnel travelling through the passenger compartment, so... I'd get them to own their work.

^ This. I had a clutch done one time and the shop did not take the time to torque the pressureplate bolts to the flywheel. I just so happened to take the clutch out to swap it for a less aggressive style clutch and noticed one of the pressureplate bolts about 80% of the way out of its thread. This could have been beyond dangerous at high RPM. Get that shop to own their work, this is a potential huge safety issue that can literally injure/kill someone.