I have a Frigidaire Gallery dryer, model #FSE447GHS0. When on, the top of the dryer is very hot to the touch. I've unplugged it and removed the dryer vent. The dryer vent from the dryer to the wall is clear of lint. I don't know what else to troubleshoot. Any ideas?

Even though the vent is clear, what is it made of? If it's that vinyl duct hose or that light duty aluminum vent hose, it is probably restricting the air flow and causing your problem. With the more rigid aluminum vent, it can be pushed back too far and bending it closed. Remove the vent hose from the back of the dryer and run a load through it. If it works properly then, you know what the problem is. That vent should be 4" diameter and old rule of thumb says no longer that 8' and no more than two right angle turns in that 8'. You can get away with deviations from that "rule of thumb" but they end up causing you problems in the long run. You can also remove your lint filter and look down in where it inserts. A lot of lint? Clean it out. Restricted air flow is the major problem with dryers of any make and loss of 1" of that aforementioned 4" diameter accounts for approx 30% of your dryers efficiency and will burn out your heater rather quickly.

JimGu - thanks for the follow up! I found the solution and now the dryer is running like a charm. The problem was just below where the lint screen slides into the dryer. I pulled out the lint screen and with a flashlight and my head almost in the dryer I saw a TON of lint. I had to remove the plastic vented guard that's just inside the dryer door. After doing that I pulled out several handfuls of stuff and then got the vacuum cleaner after the rest. Now it's working beautifully!