Clunk from park to reverse. Any thoughts on what this could be are appreciated!

https://youtu.be/JizMiaX8i6Q - Transmission to drive shaft

https://youtu.be/s8ygnv8BCHY - Rear diff to drive shaft

Truck is 2016 4x2 102k miles. When watching both clips the sound is more prominent from the rear. Only happens in park to reverse. I noticed that by letting off the brake at the right time it doesn't clunk. It also only will do this on cold starts, doesn't do it at all when it's warm.

I'm taking it to the shop to be looked at tomorrow but any input would be helpful. Thank you!

 

If universal joints are good then... excessive backlash between ring and pinion or excessive spider gear wear either way sounds like the rear end is worn out! Using the wrong gear oil would cause premature wear.

 

I’m going to expect the worst and guess that it is the rear end. Do you think changing the diff fluid could help?

 

I'm always (when going to park) put the car/truck in neutral, hand brake then parking.
never had a clunk.