Here are your parts
Parts for Whirlpool LER4634JQ2 Dryer - AppliancePartsPros.com

See the attachment for a tech sheet.

A lot depends on what mode you were in (timed or auto) as the timer motor circuit is a bit different in each mode.

I would start by checking the power. If you loose the 240 volts you will loose both timer advance and heat.
Try flipping the breaker off/on slowly a couple times. Sometimes you can loose half the line without actually tripping the breaker.
Check the voltage at the plug
L1 to L2 should be 240 volts
L1 to Neutral and L2 to Neutral, both should be 120 volts.
If OK
Unplug the unit and check the wires at the terminal strip in the machine to make sure none are loose or burned out
If OK
Check the power at the terminal strip.
Do this with the heater off and on.
[COLOR="Red"]Be careful as 240 volts is lethal !!![/COLOR]

If the timer advances in timed dry but not in auto then check the heater.
The timer gets power through the heater when the heater is off when in auto.

If power is OK and unit does not advance in either mode.
Unplug the unit and check timer Switch 0. TM to WB should be 0 ohms in timed dry. TM to OR should be 0 ohms in auto modes.
If OK
Could be that the centrifugal switch (2M/1M) is not closing when he motor gets close to operating speed or a bad wire/connection.