[fastbike]

I just did my first major towing with a 2003, 6.0 in hills, fully loaded. In the 2000 - 2300 RPM range while going up inclines, I would get a clunk noise in the transmission. Instead of downshifting automatically, it would clunk. If I manaually increased the RPM over 2500 - 2600, the transmission would downshift to the next gear with no clunk. The problem was disoncerting to say the least. The truck just turned 50,000 miles for me and I bought it used in Nov., 2005. Everything checked out great on CarFax and a Lemon Busters inspection I had performed before purchasing this truck. Has anyone had an odd transmission clunk or noise while in overdrive while towing? I feel like I should get it checked out by Ford but wanted to see if anyone had any useful info with a similar experience. Do you think a possible tranny problem like this might be repaired under warranty? Any info would be appreciated.