Two problems related to manifold/header/muffler/tail pipe have been reported for the 1999 Ford F-350. The most recently reported issues are listed below.
Dt: bought truck 11-15-01. Since then you have had repaeted problems with the front hub bearings. The 1st time they went out was 12-12-01, again on 2-11-02, and 2-14-02. Again 4-23-03. Now currently out again. In the past Ford has worked with this issue, now will not. 3-15-05 new engine was installed, now has check engine light on and knocking noises. Dealer is refusing repairs unless pays out of pocket.
Studs that kept exhaust manifold on engine block broke on right side, causing exhaust leak. This happened before on left side. Also, at 36000 miles Ford replaced motor due to engine knocking.