Here are your parts
Replacement parts for WHIRLPOOL REL4634BW1 | AppliancePartsPros.com

Here is the wiring diagram
https://www.servicematters.com/docs/wiring/Wiring%20Sheet%20-%203399125.pdf

You need heat and air flow for correct drying so try the below:
Vent Check
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.


Check your lint screen sometimes it can become coated from fabric softener residue and drastically reduce air flow. If coated clean with soap and water.

Check that the blower wheel is properly attached to the motor's shaft, sometimes they can strip out. Also make sure it is clean.

Does changing the temperature setting change the actual temperature?
Could be you have a grounded element.
To check:
Unplug the unit.
Remove both wires from the heater element.
Check between the wires, should be approximately 10 ohms.
Then check from each side to the case/frame should be open (infinite ohms)

Sometimes you can see where the element is touching the case.