[COLOR="DarkRed"]The element tested good but I noticed it didn't seem to be evenly orange when hot but I didn't see any cracks. I've been told it's either good or bad, but maybe not accurate?[/COLOR]
Check the heating coil.
Unplug the unit and both wires to the coil.
Check it with a meter, should be around 10 to 12 ohms.
Then check from each side of the coil to the case/frame, both should be infinite ohms (open). If not the coil may have sagged or broken and is touching the case. This can cause it to run on high and the thermostats cannot regulate it so the thermal cut-off blows.
The hi-limit should have regulated the temperature so the fuse did not blow, that is why there is a new one with the thermal cut-off..
Note: That unless there is another problem in the unit the hi-limit should never have to open. It is just a safety device with the fuse being a backup safety device.

Just in case it is not a grounded element.
With all the below the high limit will also have to be replaced.
Check that the belt is OK.
Check the seals (drum etc) in the unit. The air is pulled over the heating coils, through the drum and pushed out the exhaust. So any large seal leak will pull in room air and the cycling thermostat on the blower will run the unit hot.
Check that the lint filter is not coated with fabric softener residue which greatly reduces air flow.
Check/clean your vent system.
Check/clean the blower wheel.

If all OK you may want to replace the cycling thermostat as it's contacts may not be opening (welded shut)


[COLOR="DarkRed"]Possible I got a bad cut-off?[/COLOR]
Not likely.

Nope. I'm still unsure. I've validated there no short in the element, checked all belts, seals, cleaned lint (there was a good amount), blower, etc.

So on my latest test I bypassed the high-limit and ran the thing for a while to see how it works. I don't have any frame of reference for this stuff so am just trying to use logic here.

When it's running, the element gets super hot/bright orange. The vent becomes very hot and eventually the cycling thermostat kicks in (I hear it "pop"), cuts the power to the element, it cools for about 3 - 4 minutes then "pops" back and the element gets juice again, runs for about 2 minutes, opens/cuts power, etc. That seems like it makes sense to me. Super basic but I imagine that's how all these electric dryers work.

So by this logic, the element is either pure open or pure shut. Right? So what's the high, med, low setting do? The cycling thermostat is set to one temp, right?

And then the high-limit is a safety feature or just another temp? It seems like with a load of wet clothes (especially if it's over stuffed), that the hot air hardly makes it to the cycling thermostat and that the high-limit must get used all the time.

After this thinking I found what seems like a really good article here.

This article suggests the thermal cut-off fuses are easy to blow and you could potentially replace it with an additional high-limit. That sounds very tempting given that I see it appear to be working correctly. However, the safety risk (that now all 3 thermostats could fail without a fail safe seems a little worrisome). Also, I wonder if the temp dials bypass the cycling thermostat for certain temperatures making the reliance down to 2 thermostats.

I'm going to think about this a bit longer. If anyone has suggestions or recommendations, feel free to holler. I'm starting to think that high-limit and the cut-off run so close to the top end temp that it's possible that just a moderate amount of air restriction could result in this condition.

I might just try replacing the cut-off one more time to see if the latest round of cleaning (blower wheel and attached venting) was enough to get it there.

BTW, I noticed that Whirlpool doesn't make 3977394 anymore and has replaced with 279769. I assume they're identical but maybe their tolerances are slightly different making a repeat likelier?

Not sure which one of these fixed the problem, but here's what we did yesterday...

(1) I removed the Electronic Control (See item #15 at LE9480XWW1 | D&L Parts Company : Appliance Model Lookup), cleaned the contacts with rubbing alcohol and a Q-tip and reinserted it. Then...

(2) I sprayed a VERY small amount of Static Guard in the console area. (Yes. The fabric static cling stuff.) Then...

(3) I realized that when I replaced all the thermostats and the thermal cutoff kits this last time, that I also replaced the vent with one of those metal adjustable kind, because it was suppose to save me money by reducing the drying time. I put my old trusty dryer vent back on and attached it to the wall vent and...

...the dryer seems to running just fine now! Finally! :)

BTW...I can't take credit for item #1, that was my father-in-law's idea. He's an electrician and mentioned that static can build up on those electrical boards and cause them to malfunction.