Combines R72 sounds like a space ship

listen to determine if the sound is coming from the left hand pulley on the main shaft. The bearings in this pulley don't turn when the machine is engaged. Vibration can cause rough spots to develop in the bearings when the separator clutch is engaged. When you disengage the separator, the bearings start to turn again and the noise begins. If you run this way too long, the bad bearings can become loose in the pulley and_or cause the clutch plates to break. Neither one is good. My dealer mechanic says that he has put in new bearings only to have them start to fail within a year. He has come up with a promising solution of machining out the pulley hub to accept a wider double ball race bearing. He has had some machines going over two years that had been needing bearing replacement annually. Have a safe harvest Gamaman

I wouldn't say it was an annual problem, but your right it is the main shaft bearings, make it easy on your self and replace the left and right ones at the same time.. The howling noise is a dead giveaway even back on l combines.. problem is the operator won't notice it because it come on gradually..

Have replaced the seperator clutch bearings a couple of times on our 94 R62. We got a bit confused when the howl persisted after the most recent replacement. Turned out to be the header clutch bearings on the header drive jack shaft, just forward of the separator clutch. Replaced those and peace and quiet reigned again.