'83 5-Speed 4x4 Transmission Problem
 

I recently purchased an 83' 5 speed. The transmission and clutch were supposedly replaced under 1000 miles ago but the mechanic did not replace the master or slave cylinders. The transmission is making a horrible racket with the clutch is engaged (clutch let out). This happens when it is in gear or in neutral and has crippled the truck. You can hear the sound in the short video attached. I replaced the master cylinder and the slave seems to be operating properly. Any advice is greatly appreciated.

I don't think your issue is related to the clutch. Seems it is releasing/engaging normally from what you describe.

I hate to say it, but if its happening when the clutch is engaged; its likely internal to the transmission. Since its happening in all gears (and neutral) I'd expect something relating to the input shaft.

In watching your video, I seem to see a lot of movement in the trans. Is it possible the noise is coming from the trans/engine moving around? I'd take a good look at your mounts thats a lot of movement to have in your transmission.

i agree with rowdy235 on this. Check your T/C mount (it is on the cross member) and inspect your motor mounts. After 30+ years the rubber can fail at any moment

Thank you both, I will look into it and report back.