G'day busstter4.
welcome to the forum.
The clanking noise is coming from the hydraulic pump it will happen, when like you have, something reasonably heavy on the linkage the pump receives a mechanical Signal if you like from the top link and when the implement is lifted it compresses the heavy spring inside the toplink and moves the hydraulic control linkage a little bit out of sync the pump control valve floats between constant pumping and idle this is why you can hear different sounds and the engine slows down a little bit this is caused by the pump running at maximum pressure, if when you raise the linkage lever ,(the one with the square knob ,nearest you when sitting on the seat) all the way up/back and when the implement is all the way up lower it a little bit and you will hear the pump and the engine change sound.if you like you could loosen the plate on the position control quadrant and move it DOWN/FORWARD a little bit this will stop the linkage going up to far.
try to avoid operating the tractor with the pump running at max pressure.
Example :say you want to be able to raise and lower the implement and hold it at ANY POSITION IN BETWEEN use the position control lever ,leave the draft control lever( the outside lever with the round knob) all the way UP/BACK) and leave it there.
Happy days.
Hutch.