Removed moen shower diverter valve because it was frozen. Purchased new valve from manufacturer. Un able to install new diverter, will not thread in receiver. Threads do not appear to be damaged. What would you suggest?

I'm not really sure of what you have or are trying to install.

Removed moen shower diverter valve Are you saying you unsoldered
The entire valve and removed it?

Un able to install new diverter, What part are you calling a diverter? Could you be referring to a cartridge? (see image)

new diverter, will not thread in receiver Again, I you're talking about a cartridge when you say "receiver" do you mean the valve body? Cartridges do not thread in. They slip in and are secured by a copper horseshoe clamp.

Threads do not appear to be damaged I want to know what part's threaded. Back to you. Tom

Best thing to do would be post a picture of all parts.

Are you replacing entire valve or only interior part ? Photo, please. Milo