Wes D.

I have a 2006 F150 Crew Cab. when I excelerate for a dead stop I hear a thunk from the rear end. The auto tranny shifts smooth. The truck has 68k mile on it. I had the tranny fluid changed at 40K and had rear bearing seals replaced. Any ideas what my problem might be?

Help,
Wes

northeastFX4

I know exactly what that is. There is a TSB on it from this website: http://www.ford-trucks.com/tsb/fullt...p?tsb=05-26-11

ISSUE:

Some 4x4 2004-2005 F-150 (excluding Heritage) and 2006 Lincoln Mark LT vehicles build prior to 7/1/2005 may exhibit a rear driveshaft slip-bump concern on deceleration or acceleration from stops.
ACTION:

This condition can be attributable to the slip yoke of the rear driveshaft having not been lubed when the vehicle was built or wear/flaking of the spline nickel coating. Refer to the Service Procedure.
SERVICE PROCEDURE

1. Remove the rear driveshaft per Workshop Manual Section 205-01. Be sure to index-mark the driveshaft during removal to maintain alignment during reinstallation.
2. Inspect the rear driveshaft slip yoke for the presence of grease. If no grease is present proceed to step "a" If grease is present proceed to step "b".
   1. If the splines of the slip yoke are dry, but do not show any signs of wear, nickel coating flaking, or contamination, then apply 8 mL (0.27 oz.) of the new slip yoke grease, distributing it evenly around the bore. If flaking is found, then REPLACE the rear driveshaft.
      NOTE: EACH SYRINGE CONTAINS ENOUGH GREASE FOR 1 SLIP YOKE, THE PART NUMBER IS FOR ONE APPLICATION.
   2. If grease is present, inspect the driveshaft for signs of nickel coating flaking. Flaking can be found by inserting a clean rag into the yoke, wiping the spline surface and then looking for nickel "glitter". If flaking is found, then REPLACE the driveshaft.

northeastFX4

Actually, nvm I just noticed u have an 06. Might be similar to...