I have a 2000 F150 supercab 4X4 with a 5.4L. Lately I have noticed that when I put the truck in reverse and begin to back up I get a single CLUNK from somewhere underneath of the truck, possibly in the rear end(?). It doesn't clunk until I back up for a few feet and then there is no other noises. Does anyone have any ideas of where I should start to look to diagnose this problem?

Thanks!

 

Driveline - Clunk/Bump When Starting From A Stop
TSB 04-26-6

12/31/04

CLUNK OR BUMP WHEN STARTING FROM A STOP

FORD:
1997-2005 E-Series, F-150, F-Super Duty
ISSUE
Some 1997-2005 E-Series/F-150/F-Super Duty 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.

 

Thanks for the info on the T.S.B. - I wonder if that applies to 4X4's as well. I will have to look into it.

thanks again

 

I had same clunk when changing fwd/rvs found rear gears had cracked in half

follow the TSB (cheap fix's first) if that does not do it , then inspect rear

'97 F150 4x4

 

I was wondering about engine/transmission mounts, if they're failing, but the TSB sounds like the go...

 

Yes it applies to both, 4x4's are included just not stated in this one. Be sure to use the Ford Lubricants they speak of - just like friction modifier in there rear ends - use Ford Lubs - I learned the hard way and here to say , you don't have too.

Good Luck

 

I had the same problem last year, check your UV's.
And I may suggest, for the cost, replace both if you have to do one, saves trouble of pulling out the DS. Also, the strangth of a new u-joint, can kill the life of another starting to go sour.