Could not find any info on this unit.
Take a look in the control console for the tech sheet, if you do not already have it.

Is it possible I need a thermostat?
Always a possibility but I would check other things first.

TRY THIS
Undo the dryer from the exhaust
Run a load
If the load dries correctly then you have a vent problem.
Clean/check the vent system. Make sure the outside louvers open fully.

If you do not want lint in the house.
Take a pair of pantyhose, put one leg into the other and attach this to the dryer exhaust.
Leave enough room behind the dryer so it can blow out like a windsock.
Run a load.

Both the above will allow you to check the air flow and temp.
Also the above is NOT recommended for a gas dryer due to possible carbon monoxide problems.

You need air flow and heat and often the air flow is the problem.
Check the lint filter. If you use fabric softener it can coat the filer screen drastically reducing air flow. To clean wash with soap and water.
Check that the blower wheel is clean.
Most units pull the air over the heating coils, through the drum and then push it out the exhaust so any bad seal in the air path will reduce heat in the drum.

Here is a post on how to check exhaust temperatures.
http://forum.appliancepartspros...ight=exhaust+temperature
Since I do not have the I cannot be sure yours will be the same but it should be close plus/minus 20 degrees.