Over the past several thousand miles, my truck has developed the "slip/bump" in the driveline. When braking, just before the vehicle stops, and when taking off from a standstill, there would be a progressively-worsening bump. At first I thought it may of been my rear brakes draging/sticking. But after looking over the TSB's on motorcraftservice.com, I found that my symptoms matched exactly to one of the open TSB's for my truck. I took it in to the dealership. They pulled the driveshaft, and found that there were chipping flakes of metal on the yoke. They ordered a new driveshaft assembly, and installed it.
I just picked it up yesterday, and so far the probelm is completely gone! As an added & unexpected bonus, I think it also solved another problem that I've had for over a year... There's always been this gawd-awful humming sound in the morning when my truck is cold, and I'm completely stopped. I've had it in for service multiple times for this. Each time, they suspected it was the muffler system. They replaced everything from the cat back TWICE, all to no avail. The funny thing is that all along I've told them that it has something to do with the drivetrain, not the muffler. They insisted that it was impossible, since the driveshaft doesn't move when the truck is stopped. "Factory trained techs" huh??
Anyway, main thing is that all is good now. I can go back to loving my truck.
hummmm , now that you say that i've mentioned my does that just a little bit (doubt a passenger could tell but i can) moving from a dead stop.
Does it only do it when the driveline (not engine) is cold? The colder the ambient temp, the louder/more noticeable it is? When sitting at a stop light, does the humm go away if you put it in Neutral? Does it go away after driving for ~5 minutes? Those were the symptoms I had anyway.
But after looking over the TSB's on motorcraftservice.com, I found that my symptoms matched exactly to one of the open TSB's for my truck. I took it in to the dealership. They pulled the driveshaft, and found that there were chipping flakes of metal on the yoke. They ordered a new driveshaft assembly, and installed it.
Do you still have the TSB? If so could you post it? I have the same problem. They did the lube on the slip yoke. But the clunk has come back. Thanks.
05-26-11 DRIVESHAFT SLIP-BUMP ON DECELERATION OR ACCELERATION FROM A STOP
Publication Date: December 21, 2005
FORD: 2004-2005 F-150
LINCOLN: 2006 Mark LT
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.
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.
Remove the rear driveshaft per Workshop Manual Section 205-01. Be sure to index-mark the driveshaft during removal to maintain alignment during reinstallation.
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".
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.
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.
NOTE: FLAKING/GLITTER WILL BE VERY SMALL PARTICLES IN THE GREASE ON THE RAG
Re-index and install the driveshaft per Workshop Manual.
PART NUMBER PART NAME
5L3Z-19A506-A Slip Yoke Grease
Eligible Under Provisions Of New Vehicle Limited Warranty Coverage
OPERATION DESCRIPTION TIME
052611A 2004-2005 F-150, 2006 Mark LT One Piece Drive Shaft: Clean And Inspect Slip Yoke Then Grease And Reinstall Existing Drive Shaft, Or If Necessary Replace Drive Shaft (Do Not Use With 4602A) 0.5 Hr.
BASIC PART NO. CONDITION CODE
NOTE: The information in Technical Service Bulletins is intended for use by trained, professional technicians with the knowledge, tools, and equipment to do the job properly and safely. It informs these technicians of conditions that may occur on some vehicles, or provides information that could assist in proper vehicle service. The procedures should not be performed by "do-it-yourselfers". Do not assume that a condition described affects your car or truck. Contact a Ford, Lincoln, or Mercury dealership to determine whether the Bulletin applies to your vehicle. Warranty Policy and Extended Service Plan documentation determine Warranty and/or Extended Service Plan coverage unless stated otherwise in the TSB article. The information in this Technical Service Bulletin (TSB) was current at the time of printing. Ford Motor Company reserves the right to supercede this information with updates. The most recent information is available through Ford Motor Company's on-line technical resources.
If you notice, the TSB specifically mentions 4x4 models. But when talking to my dealer, the SM said that they're also applying this TSB to 4x2 models with the same symptoms, and it is infact fixing them.
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