Starter grinds for a few seconds after starting

[Engine swap]

Hey everyone,

I recently completed a clutch/flywheel change on my b13 sentra limited edition, purchased a new luk clutch kit and flywheel for a decent price and got it done over the course of a week and a half maybe 2 weeks a few hours a day.

After getting everything back in, go to try and start the car and it was a no go, loud grinding noise is all I got. Took the starter out and installed it again and it started. The grinding noise is still there but only for a second or 2 and then it clears up and she runs smooth. The car sounds normal as you turn the key and the starter engages, it fires followed by a second or 2 of grinding and then good idle. Kind of like its sticking slightly as the starter gear is pulling out. Since then I've tried adjusting any way I could think of and it doesn't get any better.

So I figured it was the starter was toast possibly. Took it to get tested he ran the test a few times for me and it came back good every time? Weird.

Has anyone ever had this problem? Any thoughts of what it might be?