I have a GE top load washing machine that agitates fine and seems to drain ok, but has a problem with the spin cycle with just a moderately heavy load. Even just a single towel or two in a very small load causes the problem.

If I do a very small load or remove part of the load, then start the spin cycle, it works properly. With any heavyish items, it starts the spin but then almost immediately stops abruptly, then runs the drain pump, and repeats the attempt to spin. It does this pattern until the timer runs out.

Any suggestions on what might be the problem or how to better diagnose are greatly appreciated! I'd love to try to fix it myself.