Thank you for replying to my car question.
I did stand the vehicle on jack-stand and had it run on fifth gear over the week-end and the following are the latest findings
1. The knocking from the differential vanishes - it only appears when the wheels are on the ground (bearing the weight of the vehicle) and driving above 20km/h
2. Left wheel spins slow as I mentioned in my initial question but something else surfaced - the left axle bearing must have been damaged. It sounded similar to a damaged wheel bear and I could feel the vibrations.
I am going to check on that axle and its bearing and replace the bearings (LHS and RHS.) Do a test drive to see if the knocking sound still exist before I will proceed to attempt on the differential work.
I will see if I can record a video of the knocking sound and post later.
I did had a look at the links after posting my initial question but thanks all the same for your help. Will keep you updated as I continue on this diagnosis and repair so others facing similar issues can use the information.
Sunday, July 25th, 2021 AT 4:45 PM