I have a 1998 lariat swb 4x4 when towing a trailer the truck vibrates and makes a rough noise when I accelerate while making a turn it doesnt do this while going straight is this the transmission or a driveshaft related issue? Sharing of any similar experiences would be of great help to me.
Thanks Bushwick

 

could be you need a tune up. Weak plugs/coils show up under a load.

 

Do you have the limited slip rear differential? Sounds like limited slip clutch chatter. It makes sense that it would show up more while towing. Some people have had success just adding friction modifier to the diff, but it would be a good idea to change the fluid and add friction modifer at the same time depending on the condition of the gear lube. 75W140 synthetic is recommended and you can get the friction modifier from any Ford dealer.