I recently purchased a used RT 622 trailer along with a used F3L. We had to drive to Springfield and get them but on the return to Texas I was following my in the car with her on the Spyder and noticed the trailer shake side to side at hyway speed. Sometimes it would smooth out but when It did the shake I could see it shake the spyder. It was empty at the time except for the Stock seat. Is this normal and if not, what can I do to fix it.