Differential Unit problems of the 1999 Ford Econoline

Rizzo Ford refused to repair it and threw me out since I reported them to Ford 3 times for insubordination and the service manager calling me a dickhead. This is also a conversion van that I purchased at rizzo, and I still cannot find anyone to work on it. It finally got "repaired" by colony Ford truck center, but with major difficulty with employees. They also took me off the road for 6 days. Needless to say, it still whines and makes noise, but started again after it was out of warranty, and this is a paratransit vehicle which cannot lose time. It's all I have. . . . . . What next ? sell it as a lemon ?.