One problem related to clutch bell housing has been reported for the 1999 Ford F-550. The most recently reported issues are listed below.
Slave cylinder needing to be replaced 4 times due to rod length not being long enough for clutch pedal travel on 1999 f550 truck with six speed transmission. Also flywheel springs breaking in flywheel causing undue wear on clutch disk and not being covered under warrenty. I have two trucks where I have these reaccuring problems and have paid each time to repair at an authorized Ford dealership.