You know what? I never thought of checking the CV joints up front. I don't feel the vibration in wheel so much as the floor, but I did notice the virbration was a good bit worse at a lower speed this morning when I used the 4x. Thanks for posting that jbrew.

I still need to get into the transfer case housing. I know I have a leak there due to all the crap that was flung up onto the under side of the bed there. I bought the seal, but the snow has kept me from crawling around under my truck. Seems to me though, that the seal is not gonna be the end all to all my troubles. Isn't the seal just sealing? How can a leaky seal put a vibration into the driveline? I'm hoping to find some sort of bearing or carrier in there once I pull the housing. I can see something like that putting in a vibration more than the seal.

 

Justuh tailshaft housing and a little cam gear for the VSS on my 98 - I'm not sure if the use carrier's or mid-shifts anymore on the 97-03 F150 models..The wheel base is longer on the 04's - they might on those..

I had to break the shaft bolts loose w/breaker bar. I couldn't believe my Ingersoll wouldn't break them... 206,000 on this 4x4 West MI truck - stock u -joints , there still tight!!

 

I replaced the u-joints a lil bit ago, and the old ones didn't seem too bad to me either. Wish everything was as cheap... then I'd have no problem replacing the whole driveline piece by piece trying to find the vibration...

What's this VSS you mentioned?

 

That's the Vehicle Speed Sensor. When my shaft is out , you can see mine in there inside the housing - the gearing running off the tail shaft..

The volicity joints on mine aren't serviceable , yours may be. Some trucks have the rubber cover that you can inject grease thru a needle - it's a regular service item if you have them.