crwdns2934241:0crwdne2934241:0 Chris

crwdns2934249:0crwdne2934249:0:

The hammering sound is obviously because of slipping of gears or cause of some obstruction.

I experienced such thing once,  I inverted the printer in the air by holding down and shook it for a while as, I suspected some obstruction and I was right, luckily some board pins  fell off.  May work or not for you the gear assembly or the belt should be checked in your case.

crwdns2915684:0crwdne2915684:0:

open