If there is a vibration or noise at highway speed, it could be from the frontdrive shaft and may require replacement of the double cardan joint. A double cardan joint is a type of driveshaft joint that uses two universal joints.
Problems for specific Ford F-150 years:
Car problem reports
Problem with your car? See what our experts say or submit your own.
Repairpal verified 1996 Ford F-150 problems
The engine oil pan gasket can develop a leak. Leaking oil may accumulate on the exhaust system resulting in a burning smell. Replacing the gasket should correct this leak.
Tubes for the EGR system (exhaust gas recirculation) can break, causing an exhaust leak and noise under the hood.
If a noise from the rear end is heard when going around turns or after driving at highway speed for an extended period, there is an updated differential clutch kit available.