I have a kenmore 80 sereies dryer, it gets hot inside the drum but takes about 6 hours to dry the clothes. Any suggestions on what to do?

How long has it been since you cleaned the vent hose?

I would disconnect the vent hose at the base of the dryer, and try to clean it out.

It is probably full of lint and does not allow enough circulation. I use a metal cloths hanger, un-twisted and straightened out to carefully poke and prod inside the hose to get all the lint out. If you have a thin hose, just be careful not to poke any holes in it.

My dryer seems to work better after I clean it, this may help with your issue.