Hi there from sweden!

I know that im not supposed to be posting issues in this section but the forum wont let me post in the correct section so here we go!

I have a 2008 ds450 that started to make a loud knocking noise on low revs under heavy load (must be in gear) so i decided to simply do a rebuild before something ended badly, i heard the sound two maybe three times before i shut the engine down.
When i pulled the engine apart i couldn't find anything that was obviously wrong with it so i swapped every bearing except for the rod bearing witch felt good and had the correct side to side movement (about 0.45mm), i measured the timing chain and it was well in specs and the same thing with the valves as well, i also put a new piston in it.
Well today i started it and the engine sounds beautiful just like it did before until i put some load on it while being under 4000rpm, the knocking sound is still there and it sounds just like it did before i pulled everything apart so now im just sitting here trying to figure out what in gods name is wrong with this thing.

I couldn't see any marks on anything that had hit something in the engine and no gears was damaged or anything like that, the clutch basket looked good aswell.
Just to make it clear, the noise is 100% coming from the engine and not from the chain.

Does anyone have any clue what the noise might be? If i drive it above 4k rpm it's perfect and when in idle it's perfect aswell, i have to be in gear and have low revs to be able to make the knock appear.

Sorry for my english, i hope that i made myself pretty clear atleast!

Best regards from sweden!