Washing machine coupling broken

I have a kenmore 90 series top loader. The spin cycle has been loud (grinding noise) and the agitator seemed to catch every few seconds and stop abruptly casuing a loud banging noise and then start back up. Now it won't spin at all and there is just a loud grinding sound during the spin cycle. I took it apart and saw the coupler on the transmission side is broken. The drive on the transmission is very hard to turn but it is able to turn. Is the transmission supposed to turn freely? I'm wondering if the transmission was causing the drive to stop suddenly and that's what broke the coupler or could it be something else?