I took my truck on a 20 mile drive the other day down to the body shop. After i got off the freeway and pulled in i backed up and the chatter was so bad i almost got whiplash. I pulled forward and it did it as well, but is way worse in reverse. I dont notice it much when i just drive it on short drives. Do you think a long drive could cause this? Clutch not adjusted properly and is slipping on the freeway? I would think if it was slipping for 20 miles it would be so burnt or glazed that it wouldnt work at all. Any insight on this? thanks