During agitation, the brake is engaged and the transmission shouldn't rotate at all. The gears inside the transmission cause the back and forth motion of the agitator. In agitation mode, the motor pulley should be rotating in the opposite direction that it does in spin mode. Pull the agitator and make sure nothing is jammed underneath it. Pull the agitator coupler and make sure the internal splines aren't stripped. You should be able to easily rotate the motor pulley by hand CCW (viewed from below) which should cause the agitator to rotate back and forth with no movement of the transmission housing.

Eric

Ok, removed the agitator and the coupler. The coupler is not stripped out at all, either the tabs that interface with the agitator, or the splines that interface with the shaft coming up from the transmission. I can free rotate the motor pulley in both directions. When doing so, the entire transmission and the tub rotate as well.

By the sounds of it, it seems like maybe my transmission is the problem? I'm guessing thats not good, probably an expensive part...

If i snake my arm up in there, I can grab the transmission housing and rotate it. When i do so, the pulleys rotate as well. If I use one hand to hold the pulleys stationary, and attempt to rotate the transmission housing, it will not rotate (the trans. and pulleys seem locked together, will not rotate relative to each other in either direction).

There does appear to be a gap, maybe 1/16" or so. I have (attempted to) attach a photograph.

Ok, the cam is stuck in the brake release position. You can replace the transmission or try to service it. You see that round ball in the gap in your photo? There are six of them placed around the cam and they sit in tapered grooves. Under that coil spring are two hubs, the pulley hub (lower) and the brake cam hub (upper). In spin mode the pulley hub is rotated such that it grips the lower half of the coil spring which causes the upper half of the coil spring to grip the brake cam hub which rotates the cam hub causing the balls to rotate out of the deep end of the tapered grooves into the shallow end of the grooves and the balls push up on the brake hub compressing the brake springs releasing the brake so that the whole transmission rotates. When spin stops, the brake spring pressure should cause the balls to move back into the deep end of the grooves allowing the brake to engage and that gap should be completely closed. Now when going in agitation direction, only the pulley hub rotates which drives the transmission input shaft. With the brake holding the transmission from moving, the input shaft drives the internal transmission gears which causes agitation. The problem you are having could be caused by dried up grease in the grooves or one or more of the balls is deformed. Normally, I would pull the tub assembly and flip it over to gain access to this area of the transmission. It is possible though to lay the machine down and remove the bottom panel. Iv'e never done it that way and I think it might be difficult to get the balls back in there once you've taken it all apart, cleaned it and greased it, with it laying on it's side. I have some good photos of disassembly if you want to tackle it. You might get lucky if you just remove the pulley and coil spring, get some grease into that gap between the hubs and work the brake cam hub back and forth by hand to break it loose and functioning again. Just don't get any grease on the hubs under the coil spring or inside the coil spring or it won't grip anymore.

Eric