Five problems related to differential unit have been reported for the 1998 Ford F-150. The most recently reported issues are listed below.
I purchased a 1998 Ford F-150 in 2000 from carmax in arlington, TX. I have had no major problems until Nov. 7th 2008. I was driving and approached a traffic signal. I attempted to depress my brakes when the vehicle locked up and spun sideways at the intersection. When I exited the vehicle I found that my driverside rear differential had broken lose and the rear differential clamp had broken off allowing the entire driverside differential to fly off of the vehicle. % minutes earlier I was on the freeway. If this would of happened on the freeway, I would not be here today.
The differential has disintegrated inside. This was caused by a bearing which came apart and caused everything inside to shift about an inch towards the drivers side. How dangerous is that? ultimately, the housing, ring gears and other gears inside were damaged beyond repair. It started with a slight hum at 45 mph and within two weeks completely broke so that the driveline turns within the housing while the wheels stay put. I use my truck only for street transportation and have taken impeccable care of it. The truck has 102,000 miles on it. Only two months ago, I had the fluid changed everywhere including the rear end. I have put a rebuilt rear end resulting in $2600 out of my pocket. Thanks mr. Ford for that!.
Differential gears attached to transmission, hole the oil for transmission. Differental is dripping every day because seal that holes it in securely is defective.
Differential unit broke on two occasions, and been repaired/replaced under warranty by dealer. Problem reoccurred again, and dealer refused to repair due to warranty expiring, but still knew that this was a defective part. Feel free to provide any further details on this matter.
The bearings burned out on the differential. Dealer contacted and replaced the differential under warranty.