It's a Magic Chef (Maytag) CAV4000AWA, 24 years old. Have replaced the drive belt, snubber ring, and springs over the past few years. Recently the spin cycle speed has become slow and the clothes come out wet. Everything else is fine. It makes a slight intermittent clunking noise when agitating and spinning.

I have read that it could need a new thrust bearing. Anything else I can look for before ordering the parts and tearing into it? How can I tell if the transmission is the problem?

Well I bought the thrust bearing kit from a APP and installed it tonight. Spin cycle works great now and no more clunk noise.

One problem I had on the install I will share in case others have the same problem. Installing the retaining clip with the .032 washer was virtually impossible without removing some material from the hub of the pulley (the portion that sits in the thrust bearing collar) to expose some of the shaft groove. After doing that I could see about half of the groove exposed so then I decided to bevel the leading edges of the retaining clip so that they would fit in the groove. Then when I drove the clip in with pliers there was a wedge effect that tightened down the cam about the right amount so no more adjustments were required.