I have a 10-year-old Frigidaire Crown Series dryer, model CREF342AS1. A couple weeks ago the drum stopped turning reliably. It would rotate a couple inches and then just stop. I could let it rest a bit, and then it would rotate a few more inches, and stop again.

I disassembled the dryer to clean and relubricated the ball shaft, bearing, and tensioner wheel. I reassembled it and the problem persisted. I removed the drum and tried to power just the motor; the motor wouldn't rotate: problem discovered!

So I ordered a replacement motor from this web site. Installed it last night. Everything looked good at first -- I tested it (on air only, no heat) and everything appeared fine. I closed it up, stacked it back on the washer, and started to dry a load of clothes.

After about five minutes, I noticed what started as a quiet thumping sound -- about two thumps per second. Within a few seconds the volume increased and got quite loud. I removed the clothes and ran the dryer empty; the thumping persisted. When I let the dryer cool down, the thumping went away.

I have tried three different greases in the bearing and two different oils on the tensioner and I can't seem to get rid of this problem. When the drum heats up, the thumping sound starts, and just gets louder and louder. When the drum cools down, the thumping disappears.

Some sort of thermal expansion appears to be the cause -- but which parts? Note that this problem didn't exist before the motor died, so it's really mystery. Thanks to anyone with some ideas.

Sorry for the late reply.

I double-checked all the alignments of the parts, everything appeared fine. Since I had the thing torn apart anyway, I ordered a replacement blower and a "maintenance kit" that contained new a belt, pulley, bearing, bearing cup, pulley, and felt pads. I swapped out the old parts for the new ones, put everything back together, and now the dryer works perfectly. I think it's quieter now than when we first bought it, even.