I am in sales for a company that sells maintenance fasteners (nuts and bolts) to Ford. One of the plants I deal with is Ford Kansas City Assembly. My rep out there was able to give me the number of an engineer at the plant. In my talks with him he believes it is drive shaft related.

I was able to go in to the dealer where I purchased. A tech rode with me and said the vibration seemed similar to another he had worked on. Monday I am scheduled to drop it off to have a "ring and pinion" replaced in the rear end. The service tech will be advising the engineer to see how this works. The service manager said he thouhgt all the TSB's sent so far have been a waste of time. Hopefully I am getting somewhere. I will keep this thread posted.

I had taken the truck to the closest dealership to me, but installing the damper kit, they drove a truck off the lot and said it must be normal and told me that's all they would do.

 

Thanks man, I have a feeling this is all going to be resolved pretty soon. I am glad somebody has talked to "someone who might know". Sounds promising.

 

I believe thats the second Ford Engineer to say its a drive shaft issue!

 

I'd have to agree. The only thing that had any influence on the vibration was when they added shims to the driveshaft on my Lariat. The vibration was reduced and the worst vibration is now at 40 - 42 mph instead of 46 - 48 mph. The vibration is not as bad and is only between 40 & 50. It's still darn annoying though.