Roper dryer vibrating

[rancherman]

have a RED4400Vq1 Roper dryer that's been bugging me all winter. High frequency vibration that really gets the sheetmetal cabinet humming.
I replaced the 2 rear rollers, front and rear 'bearing/seal' and the belt+tensioner, even though they didn't seem worn/loose/tight..
As bad a shape the rear seal was, I thought some of the vibration was due to chatter from running on a crusty surface.
Much like a steel shaft in a dry bushing can 'chatter'.

After putting it back together last night, nothing changed in the vibration dept. So, is this a motor/bearing/fan balance issue now?

side bar: dryer won't heat, or heat enough for the 'auto sense' part.. it quickly advances to 'off' like, in 10-15 minutes. Little to no drying or heating has taken place.
On "timed high heat" it works fine. There are no sensors in the drum, just the thermostat in the fan housing. Is this the culprit?

 

[rancherman]

just got done running the dryer minus the drum. It's definitely in the motor/blower. Cannot feel any tell tale signs of bad bearings in the motor.. radially, or axially.
May have a blob of crap stuck in the fan, or a broken fin or two...

 

[DADoES]

 
Auto-dry on your model works by temperature, cycling the timer opposite of the heating element.  Does it have one auto-dry cycle for high heat?  Or two auto-dry cycles, one for for high and one for low heat?  If two, both don't work?

 

[coldspot66]

Blower wheel could be stripped.

 

[rancherman]

update

so, a big nail got past the screen, and wiped out a couple fins on the blower wheel.. It happens.

This dryer only has 'high heat' on the auto-sense. Then it's got timed high, low, and no heat (fluff) Far as I could tell, all the timed cycles work as they should.

I'm going to ohm out the cycling thermostat.. but something tells me it's in the timer: if the cycling thermostat was 'bad', it shouldn't work in any of the cycles. Right?