I have this problem and found this TSB.

TSB
05-26-10


* CLUNK OR BUMP WHEN STARTING FROM A STOP

Publication Date: December 21, 2005

FORD:
1997-2004 F-150
1997-2006 E-Series
1999-2006 F-Super Duty

This article supersedes TSB 04-26-6 to update the affected model years.
ISSUE:

Some 1997-2006 E-Series, 1999-2006 F-Super Duty, 1997-2003 F-150 and 2004 F-150 Heritage 4x2 vehicles may exhibit a driveline clunk or bump that occurs as the vehicle starts to move forward, following a stop. This condition may be caused by the slip yoke not sliding smoothly on the output shaft splines.
ACTION:

Lubricate the slip yoke with Motorcraft PTFE Lubricant. Refer to the following Service Procedure.
SERVICE PROCEDURE

1. Verify the condition.
2. Remove the driveshaft per Workshop Manual Section 205-01. Be sure to index-mark the driveshaft during removal to maintain alignment during reinstallation.
3. Lubricate the slip yoke with 7-13 grams (0.25-0.46 oz.) of Motorcraft PTFE Lubricant.
4. Re-index and reinstall the driveshaft per Workshop Manual.
5. Verify the repair.

My question is: Which slip yoke are they referring to? Is it the one at the rear diff?

David

 

Yes, but I did both of mine.

 

Mine was clunking a lot this winter but stopped when things warmed up. Dealership didn't seem to know what was going on. I will save this TSB in case it starts again next winter. Thanks for posting.

 

Rear drive-shaft has a slip-yoke - that's what they're talking about.

I did mine 2 years ago, with the PTFE grease from Ford, and it's been great every since. Did it since brand-new, for 4 years. Took it apart, everything was 100% perfect. Greased it, put it back, and not a problem since.

Many people report having to relube the slip-yoke every year or even more, but mine has been perfect ever since.