Originally Posted by Fenwick223

Ok, here's my latest saga (after my intermittent starting problem). Since I purchased my '04 XF almost a year ago, I have been hearing a "humming noise" from the rear end. It was really noticeable at higher speeds especially when pressing and releasing the gas petal. After researching this issue on this forum, I took it to one dealer who said "don't worry about it" which was not the answer I wanted to hear; I wasn't "worried" but knew it was right to be making the noise. I took it to a second dealer who said it was a common problem with the differentials on some of the earlier XF's. They ordered a new one which turned out to be on "nationwide backorder" and it took about 7 weeks to get it in. Thankfully the car was driveable and the problem was really just annoying. When the part finally came in, they called and the repair was promptly made. I picked up the car and proceeded to drive about 3 miles when I heard a BANG, then a THUD, and finally just GRRRRRR and my baby died beside the road. The spot where it happened to die was on the Washington DC Beltway, right at the exit to Rt. 66 West. This is about the last place anywhere that you want to break down. Anyway, needless to say I was not pleased (understatement). I called the dealer immediately and within 30 minutes they sent their Courtesy Van to pick me up. They also made arrangements to have a flatbed tow truck pick up my XF. They gave me a loaner (300 Touring) and ordered another differential. It took 8 days for the new part to arrive and be installed. This time I told the service manager to drive the car home and back before they declared the problem solved. On the day it was ready, he called to confirm that it was ok for him to drive the car home and back and I told him "yes" it was. The next day I picked up the car and it is running fine and, best of all, the "humming noise" is gone. All I hear when I accelerate is the sweet sound of the exhaust.

In the end, Koons Chrysler in Tysons Corner, Virginia, got the job done. It took patience from all parties, we worked together, and we kept smiling even though there were times when I could have really lost it. I was able to speak directly to the XF tech who was really at a loss to explain what happened (and yes, he assured me that there was oil in the differential). All they could say was it was a defective part. I do have the MaxiCare warranty which is a good thing because the total bill for the work was $3,300 (and they did it TWICE). Out of pocket cost was $100. Even with what happened, I would not hesitate to take my XF or other cars to them for service. (FYI, they only charge $75.47 for an oil/filter change on the XF.)