400 Backhoe sudden knocking/ tapping noise?

[ryan19804]

My backhoe with the 4 cylinder 202 engine has suddenly started making this knocking / tapping noise, it sounds like it's coming from the engine.

I pulled the valve cover off, all valve's appear to be opening and closing.
I loosened the injectors one at a time whilst it was running and the noise didnt go away
Oil level and hydraulic fluid level are both at min mark.

Im unable to upload a video on this forum so instead i've uploaded it to youtube, it would be wonderful if any of you knowledgeable folk could have a watch.

Any advice would be greatly appreciated!

Thankyou

 

[Tx Jim]

Check front hyd pump drive coupler for wear. If frt pump drive is good then I suggest to check injectors.