Hi. New forum member, but I have experience with this.
I'm active-duty Navy, and stationed in Okinawa until earlier this month. I have sent back a 1989 Land Cruiser and it's on a boat somewhere in the Pacific right now (see avatar), coming to San Diego sometime in August/September.
To get to this point took a tremendous amount of Japanese and US government paperwork and effort, so much so that by the end, it left me questioning the value of doing this.
1) You need to have owned the car for 90 days prior to trying to move it. I can't cite an actual instruction; this is what was told to me by the guy who did my paperwork to move the car.
2) Your orders from Japan back to America need to have a specific TAC code that basically says that there's money to move your car at the government's expense. Your local Transportation Management Office (TMO) or DMO (Distribution Management Office) should know where to find this code.
This is how the USAF stopped moving cars - they stopped the money flow. They took out this TAC code from the military orders stating that the government would pay to move a car. The Navy, Army, and Marine Corps have left this code in their orders.
3) When you PCS from CONUS to Japan, the government lets you store a car on Uncle Sam's dime for the duration of your tour. If you have a car in official government storage, you CAN NOT ship a car back on the government's dime.
4) The car has to be older than 25 years old from build date (mm/yy) to be imported and exempt from CBP and EPA rules.
5) The car has to be clean (washed and vacuumed), and in safe/operarable condition (no cracked glass, no leaks, working brakes and lights). Also, no active recalls on the car, and LESS than 1/4 tank of fuel.
6) Call the title division of whatever US state you plan to register your car in, to find out their title requirements for titling and registering an imported car. Ohio requires a "professionally translated" title, because my Cruiser's title was entirely in Japanese.
Assuming your car qualifies, you go to your TMO/DMO office, fill out a "POV PCS" paperwork packet, and they send it to the Vehicle Processing Center (VPC), and you call the VPC to schedule a vehicle drop-off appointment.
At your drop-off appointment, the inspector inspects the car, confirms all of the above qualifications are met, has you fill out an USDOT NHTSA form HS7 saying it's older than 25 years, and the EPA form 3520 saying it's older than 21 years old and thus exempt. The inspector takes your keys (be sure you have a second set, for when you pick up your car) and you CAN NOT drive that car any more.
This is where it gets fun. Now, you take your OTHER CAR (you have two, right?) and go to the Japanese Land Tax Office to de-register your car from the Japanese vehicle registration system. You sit in some lines, get some money back that you paid for Japanese annual road tax, and they issue you an "Export Certificate" that allows you to export the car. You take the Export Certificate BACK to the VPC and then they put your car on a boat.
Then, you drive to base Vehicle Registration to de-register your car from the US system, and then they'll stamp your check out sheet so you can actually leave the island. If you don't have another car, you're going to drop literally hundreds of dollars and hours of your life on taxi rides taking you from place to place.
Right now, I'm waiting for a call from the San Diego VPC to tell me my truck is ready for pickup. Or that it fell off the boat and is at the bottom of the Pacific. Who knows?
