2005 225 etec lower unit issues

So I'm thinking I have a lower unit that went out the reverse gear is working as it should the neutral is working but when you place the motor in forward it clunks and shakes. Once the issue was found my son just left the motor off and trolled back to the ramp nothing was hit and was running fine until he went to start it up and move spots. Is it possible that the shift cable my be the issue. I have yet to drain the lower unit fluid to look for metal chunks is there something that i may be missing. I'm driving back home to take a look and help or pointers I would be thankful. I tried to attach a video but it says the file is to large and I know as much about computers as I do my outboard issue.
I have the video if someone can attach it for me

Not trying to be a butt head but seek professional help. Could be a bad clutch dog, bad pinion or forward gear. You could pull the bearing carrier and reverse gear and have a look.

Trust me I'm not offended I just wasn't sure if there was something obvious that I could look for before I take it in. I am a little concerned with a lack of parts issue.

Plenty of gearcase parts available.