I replaced mine on a recurculating heater, no big deal. I made the mistake of ordering one that said it was correct for the year but turned out to be the wrong size shaft. Some are 1/4" and some are 5/16". I think the fresh air may be 5/16". Got mine at Oreilys for $30 and it had a bushing with it to 5/16". Check the thread in electrical forum for the part number if needed.

If you never tell a lie, you never need to remember what you said.