How to find thecapacity of an older model dryer

I think your earlier info about main bearing or roller guide wheels sounds good. Let me recommend RepairClinic.com, they have a section there on repair help, common problems, and specifically noisy dryer. They typically recommend replacing guide wheels, etc, for noise issues. Let me recommend AGAINST soaping the belt. That sounds like a bad idea. If the belt is what transfers motor power to the drum, to spin the drum, soaping it (which would reduce the friction) sounds very bad indeed. Hope this helps.

The heating element would not work at all if a leg is broken. If the clothes were warm when it shut down, then it clearly just happened. The online wiring diagram is virtually impossible to read, but it appears the heating element is interlocked through the motor controller. It's conceivable that if one part fails, the other is shut down, but it's impossible to tell from what I have available.

It makes complete sense to go ahead and repair the heating element since it is obviously broken. Don't worry about thermostats etc. at this point, fix what's broken and go from there. There's a fair chance that's all that's wrong.