Need shifter help

This is probably a very basic question, but before I break something or hurt myself I thought I better ask.

How do I get the shift arm off my 4L80E transmission?

I am installing a kugel components column shifter linkage kit.

I tried wrenching it off left and right, but nothing is budging.

Any advice?

Thank you

It is probably corroded. Squirt it with a good penetrating oil and let it soak for an hour. Then repeat. At this point, try the wrench again. If it is really bad, you may have to use heat.