Hey, I have been messing with this washer recently, a Whirlpool LA5200XTWO, after my mom called me to tell me it quit working. After some diagnosis I decided the motor was bad. It would shake badly even out of the machine so I figured the bearings had gone bad. I bought a new motor and installed it, but something was still not right.
When set to “run” the washer would fill fine, but at the start of agitation it would run kind of slow and make a kind of knocking noise along with the agitation. However, when in rinse mode it would agitate quickly and without any knocking. This made me think it might be the timer, so I disassembled the timer and sure enough a few of the metal "fingers" were melted with pieces of plastic burnt around them.
So I bought a new timer and installed it and everything seemed to start and run fine. Then about 3/4 way through the cycle it started agitating slower and making the knocking noise again! I would reset it to the beginning of the cycle and it would go away, only to start back up sometime after. Still rinses, spins, and drains perfectly fine.
I would think it could be the transmission, but it will agitate fine at the beginning of the cycle and during the rinse, so the transmission can't really be the culprit. I don't really know what else could be the problem, although I will admit that washers are not my forte.
Any help would be GREATLY appreciated. This washer is about to drive me up the wall.