Hey all,
I have a 97 F150 ex cab with the 4.6. When I come to a complete stop, and start going again, I get a sound from the rear of the truck, like a gear skipping a tooth or the brakes sticking. Anyone got any ideas? Just bought the truck last August, has 116k on it. I havent changed any fluids besides engine oil. Anyone had this problem?

 

Sounds like a bad u-joint

 

I also have a 1997 F150 4x4. Mine does the same thing and I only have 61,000 miles on mine. I have changed the U joints, rear axle fluid, Transfer case fluid. Then I read a TSB regarding F150 rear end clunk. There is also some information on this site regarding the clunk. Apparently the drive shaft splines hang up in the trans output shaft upon acceleration. The fix for this problem is to remove the driveshaft and apply Teflon grease to the splines on the shaft after cleaning it with brake cleaner or equivlant. I performed this "fix" and it worked for a while but the clunk is back again. You may very well have a bad U joint as someone else suggested but just something else to consider. Good luck.