Here are your parts
Replacement parts for WHIRLPOOL LER4634PQ0 29" Electric Dryer | AppliancePartsPros.com

Here is your wiring diagram
http://www.servicematters.com/docs/wiring/Wiring%20Sheet%20-%208528187.pdf

You have a very weird problem so it may be a pain to find.

I would try the following first
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.

If the above does nothing
Put the unit into an Auto cycle
Does the timer advance?
When in an auto mode, this unit's timer receives power through the heating coil when the heater is turned off
This is checking to see if the heater has a break that opens when it heats up and does not re-connect till everything is back to room temperature.
If the timer does not advance odds are that the heating coil is the culprit.