[BirdOPrey5]

If the forum is getting the more traffic it seems logical to move the store domain over to the forum...

More logical would be to change the store domain to be a "parked domain" at your forum domain so that in effect both URLs go to the same site.

forumdomain.com/forums/forum.php
storedomain.com/store/store.php

Both will run off the same server so if you typed in

storedomain.com/forums/forum.php
or
forumdomain.com/store/store.php

both would still work.

You'd have to move your store files and database to the same account as your forums, and also keep the same URL structure.

I n the end you'll keep your initial traffic from both sites, but going forward you only advertise/link to your store with your forum domain.

You can use a 301 redirect to redirect people using the old store domain to the new forum domain.