I have a 2004 Longbox F150 with 80k miles and I got a screwed up driveshaft problem.

My longbox has a 2 part driveshaft, i'm not sure if they all do or not. Anyhow there is an expansion joint just behind the center bearing to allow for expansion/compression of the drivetrain. This can also happen at the transfer case insertion point. Anyhow this expansion joint on my truck somehow wasn't lubed enough (dust boot was undamaged) and was seizing. It completely compressed taking the slack out of the point where the forward driveshaft goes into the transfer case.

Anyhow this was just enough movement where the center bearing slid out of the rubber isolator that it sits in and started grinding on its bracket. Screwed up.

Anyhow I removed the boot, lubricated and slid everything back into place and it appears to be okay. But I just thought I'd let everyone know in case they ran into this problem what the cause was. If you are under the truck and see an excessive amount of shiny driveshaft coming out of the transfer case your truck might be headed this way.

This problem may be exclusively Longboxes due to the stackup of these parts or my truck or who knows.

not real excited that this happened, but whatever...no parts I guess.

4th lubrication problem thus far (parking brake, spark plugs, axle seals, driveshaft)

anyhow,
keep on trucking

-ii