"Rumble" noise from Kenmore electric dryer

I have a 20 year old Kenmore electric dryer (essentially a Whirlpool). It's held up pretty good overall. About 4 years ago the motor wouldn't turn, so I replaced the motor along with the rollers, belt, and front and back bearings. Everything has been working fine since then (it was running quieter than when it was new!).
About 2 weeks ago we started getting an intermittent rumble/heavy vibration about every 10 seconds or so. It would only last a few seconds, but it would really shake the dryer. Sometimes it's worse than others.
I figured one of the rollers was loose or worn and I took it apart to check it. However, I'm not seeing anything that seems like it's out of alignment. The front and back bearings seem OK and I don't see any play in the back support rollers. The fan wasn't replaced 4 years ago; it's still the original one, but it doesn't seem loose or have any damage on the blades except a few tiny nicks and scratches.
I've done some searching using words like "electric dryer rumble", but most of the hits seem to point to worn out bearings, rollers, or blower wheel, and as I said those are all in good shape and/or fairly new. I may go ahead and replace the fan; it's about the only original moving part on the dryer.
A dryer is such a simple item, but I don't really want to have to scrap it if it's something fairly easy (and inexpensive) to replace.
Any suggestions would be appreciated.
- Mike O.
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Any irregularities on the belt?
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Hi,
Check the motor mount and the two mount clips.
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I thought about that, but the motor seems very tight. Both clips are solidly attached, there is no play in the motor mounting. I ran the motor with just the fan attached and it's very smooth.
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have any problems.
The other thing that's odd it that the rumble doesn't seem to be in time with the drum rotation; it seems like the vibration times are farther apart than the diameter of the drum.
I also checked the fan. It's very solid on the motor with no "wiggle". I ran the motor with just the fan (on the "air" cycle, with no heating!), and it is very quiet and smooth, so I don't think it's the fan.
I did notice one thing on one of the rollers. It doesn't wiggle on the shaft, but it looks like it's not quite perpendicular to the shaft. As I rotate it, and you look at it along the edge, it seems like it's warped. Kind of like if you're looking down on a bicycle wheel that's warped, as it rotates the tire seems to wobble. It's not much, probably about 1/4 inch, but could that be causing it? Possibly some kind of harmonic vibration along with the drum, belt, etc.? The other roller is perfectly straight. I could replace the roller, but don't want to if I don't have to.
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That roller could make the belt ride funny on revolution #1, but not funny enough to make a rumble until revolution #2. Maybe.
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Idler wheel 'scrubbing' as drum turns. In same way a vehicle tyre may 'scrub' as you make a very sharp turn at slow speed???
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I'm not sure what you mean by "scrubbing". However, I was also wondering about the idler. It seems to be in good shape, the mounting arm is very "springy" and the wheel rotates freely. However, it's one of the few moving parts I didn't replace 4 years ago when I did the other rollers. The only thing is, as small as it is, I would think it's spinning pretty fast; the vibration seems to be a lower pitch than I would expect from something moving that fast.
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wrote:

If this was a Maytag I would say the blower wheel was loose on the shaft. It makes that kind of noise. Not sure about Whirlpools
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I saw that info on the searching I did. The blower on this is plastic, but it has a threaded insert imbedded into it that the motor shaft screws into. After seeing the articles, I checked the blower, it was very solidly mounted, no play in it at all when I moved it.
I'm wondering if it could be the idler wheel. It seems OK, but it's one of the few moving parts that I didn't replace about 4 years ago.
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wrote:

OK I guess Whirlpool is a better machine than Maytag
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