my dryer is spinning but will not heat. already replaced the thermal fuse and the heating element, but still no heat. got a meter this morning and tested the ohms, everything is at zero except for the thermal cutoff. so am i correct in assuming thats the problem?

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Replacement parts for WHIRLPOOL RED4340SQ1 29`` ELECTRIC DRYER | AppliancePartsPros.com

Yes it looks like you found it but there are other things you may want to check.
I am assuming the fuse you replaced was the one on the blower and the thermal cut-off that is open is close to the heater ( Item 6 in Section 3)

You have to find out what caused it to go.
Note: that sometimes they do just blow on their own but changing it without checking other things is a gamble. I believe richappy (another regular poster on this forum) has done a study on thermostats and found a wide variation of actual trip point and what is specified.

Check the heating coil. You have replaced it so cannot do the below so I would replace both the thermal cut-off and the hi-limit. They come as a set Item 6 in Section 3.
So the [COLOR="SeaGreen"]green[/COLOR] text is just FYI.

[COLOR="SeaGreen"]Unplug the unit and both wires to the coil.
Check it with a meter, should be around 12 ohms.
Then check from each side of the coil to the case/frame, both should be infinite ohms (open). If not the coil may have sagged or broken and is touching the case. This can cause it to run on high and the thermostats cannot regulate it so the thermal fuse blows.
Did you notice a short to the case when you replaced it?

If the above is OK, it will be because you replaced it.
Then you will also have to replace the hi-limit as it should have regulated the temperature so the fuse did not blow.
Note: That unless there is another problem in the unit the hi-limit should never have to open. It is just a safety device with the fuse being a backup safety device.[/COLOR]

You still have to find out why it blew.
Check that the belt is OK.
Check the seals (drum etc) in the unit. The air is pulled over the heating coils, through the drum and pushed out the exhaust. So any large seal leak will pull in room air and the cycling thermostat on the blower will run the unit hot.
Check that the lint filter is not coated with fabric softener residue which greatly reduces air flow.
Check/clean your vent system.
Check/clean the blower wheel.

If all OK you may want to replace the cycling thermostat as it's contacts may not be opening (welded shut).