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..?
Mine does the same exact thing. Drives me nuts! I replaced the ujoints with zero change. Clocking the driveshaft changes the vibration so it makes me believe it is the culprit. There is play in the slip yoke (torsional) but no up and down. Is your driveshaft a single ujoint at either end and the slip shaft at the transfer case end? I heard rumors some Excursions had a double cardan shaft from the factory. Anyway, I have a lot of negative pinion angle. Some research found that Ford was shimming the rearend to get less pinion angle. I may try that. Good luck! Let us know what you find.
My shaft has a single u-joint at each end with a slip yoke/slip joint. Overland said that there should not be a zerk fitting for the slip yoke (which there is) and warned that I should Never grease it. Apparently grease will fill the joint and create a vacuum and will force the DS to "hammer" the axle and transfer case. It should be pulled apart and greased and then slid together and completely flexed.
Overland said the DS was way out of balance, they took every factory weight off and added three huge weights.
Put the freshly balanced D.S. in this morning. What a difference! No noise and smooth as silk!
Oddly enough my F150 work truck was diagnosed with a bad drive shaft yesterday at the local shop. Was told by the dealer that it needed a new rear end...the local shop replaced the drive shaft and its good as new.