I had to have a friend pull home my 66 the other day. We drove no more than 25mph for less than 5 miles. The next day I started the car to drive it around to my back driveway and it seemed to have trouble pulling. It acted like this before when I started it for the first time after 6 years of sitting still. After I topped off the fluid it was ok. I checked the fluid and its still ok. Should I worry?