"It is not the same thing."
Translation:זה לא אותו הדבר.
Not quite. Mailman only sounds the same but is spelled differently - דוור. Car both sounds and is spelled differently. אוטו with the emphasis on the first syllable (like AUto in English) rather than אותו with the emphasis on the last (otTO).
And... To kill the joke completely... We would rather say האוטו של הדוור The car of the mailman
The other form is getting rare as it is, and uaving a foreign word (אוטו) makes it all the more weird.