Freidian slip? What I said at work

Years ago a young girl came in, I was also young back then, and told me her Dad had sent her down to have someone check the oil in her 4-speed transmission. Without even thinking, I asked "You want me to check your rearend too? She gave me this funny look and I finished up saying "differentiaL" and she said "sure I guess" As I was checking everything she just stood there watching with this little smirk on her face. I think it made her day too!!!