Hi All. I have been trolling this forum for about 6 months since I purchased my 03 ex 6.0, 4x4 last August..... thank you all for the great information.

I would like to give a little back if I can...

I noticed a drive line vibration/noise while on a road trip from CT to MI this last December (my truck has 50K which seemed a little premature for U-joints or rear end problems.). After 20+ hours of torment, I was convinced the noise was the U-Joints. The noise was most noticeable at 70+ mph and could be described as a sort-of growling/grumbling roaring noise that resonated in the cabin (although my wife seemed somewhat oblivious). It seemed to go away for a split second when I lifted off the gas then transition to a deeper "unwinding sound" (still a vibration/noise) as the truck decelerated. Upon arriving in MI, I made my way to a local auto parts store and promptly replaced both U-Joints - thank you Ford-trucks for the procedure info. Unfortunately the 20 hour return trip proved that the u-joints were not causing the noise. Incidentally the old ones looked fine when I removed them.

Since the trip, the Ex has been keeping the snow off the driveway and occasionally made a short grocery store run, so needless to say I haven't given much thought to the mysterious noise. A recent ski trip to Vermont was enough motivation to have the rear axle fluid changed. The fluid was dark and a little metallic however the fresh synthetic didn't do anything for the noise.

After a few phone calls I located a GoodYear service center that supposedly was pretty good at "heavy Duty" drivetrains. The mechanic offered to go for a drive with me and listen to the noise. He was very knowledgeable (had been a ford Diesel guy) and while driving the truck he explained how unlikely it was that the rear end was bad. - apparently it would be extremely rare with my low miles. He was pretty sure that it was the drive shaft.

So on Monday I pulled the driveshaft out and took it over to Overland Drive Shaft in CT. I just got the call and Overland said that the driveshaft "shook the whole machine". They ballanced it for about $100.

I can't confirm 100% as its not back in the truck, but it sounds like we may have found the culprit. As soon as I get it back in later this week I will re-post my findings. There was one key thing the mechanic that drove the truck said...he said there definately was a vibration in cunjuction with the noise (which I felt as well) and that rear axles don't usually make a vibration- they may howle and wine and growl and leak, but they don't vibrate. I hope this helps anyone else out there facing driveline noise. It would be interesting to hear if anyone else found this fixed their noise..?

Thanks again,
Clint