Hello,

Hope someone can help me figure this out

My 87 suzuki samurai will make a really loud knock sound when accelerating from standing still, it will happen when moving forward, and backwards, usually it will only make the sound when moving forward after previously moving backwards and vice versa, as if something was moving back and forth and hitting an end stop

I can prevent the noise from happening by releasing the clutch very smoothly

Being driving around like this for a few months but now I'm about to make a really long trip and want to make sure everything is perfect so I placed a camera underneath the Samurai and recreated the condition, when releasing the clutch quickly enough, the entire rear axle will rotate and seems pretty clear that the knocking sound comes from this play

The leaf spring bushes are completely worn, so I will replace them, but I am not 100% sure those are the root cause of the problem, or the only one

Hope someone with experience in the axles/suspension can help me out, link to the video below:

https://youtu.be/OONA16FlFfQ

Thank you!

Wow, ok.  That looks like more then just the u-joints binding up...

I would put the rear end on jack stands, disconnect the rear driveline and move things by hand, you should be able to feel where it is binding up.  It looks like something is binding up in the rear end, did you change the gear oil and look for any metal?