You can get a 3/4" pipe tap at your local sears tool department, Also most auto parts stores will have one, like NAPA, Car Quest, etc. You might even be able to rent one from Lowe's or Home Depot, if you don't want to buy it. A thread file will work also if you can get one, but it will be harder to use.
05 Alfa Gold 40' Motor Home "Goldie",
03 Malibu Toad
in a 24' CargoMate trailer.