Ford taurus downshifting?

I went to a mechanic I know telling him how my 03' ford taurus downshifts hard when I stop. Not when I accelerate. It's just a little jolt when I stop. I will be going on an 8 hour trip and I'm trying to make sure I don't need to get it fixed. He said it was fine but I'm just making sure

Shouldn't cause any major problems, you just might need a new transmission sometime soon