NHTSA complaint #11654244

Owner complaint summary

1st noticed problem- turning sharply to the right heard clunking coming from under car. Put car into reverse and felt like brake was on. But wasn't. Clunking stop when put back into forward and parked car. One hour later, drove a mile and a half home. No clunking until I backed into driveway. Clunking stopped after going in reverse about 10-15 feet. Drove to Dealer next morning. Couldn't get clunking to happen at quicklane. A few days later went to lunch and was backing into parking spot and clunking returned. After lunch drove to Dealer. They witnessed the clunking. Put car on hoist and checked obvious spots nothing found. Provided loaner and after determining differential was the problem. (almost $5000.00). Problem repaired next day. Had car about 2 weeks and clunking appeared when we were 3 hours away from Dealer. Called and made it to the dealer before closing. Clunking was noticed and this time at the dealer the transfer case was the issue. (Another $5000.00). They said this was the cause of the differential problems. After waiting for a week for ford to release a new transfer case, the car was again repaired. The mileage range of 400 to 1000 was given for the parts to get back in sync and stop making the clunking. We have now have about 600 miles after the last repair and an occasional clunking is still appearing. One more note. We will be traveling to Michigan from Florida in 2 weeks. (1771 miles). Is this car a lemon? Issues started after 60,000 checkup was done.