Well here's the deal, I have a 97 F-150 4x4 and have had this irritating clunk since I got it a couple of years ago. It happens from a stop and go. I had everything from the u-joints to the rear end checked. My dealership and I have finally came up with the answer that its my slip yoke that enters the transfer case. Everytime we re-grease it with Ford's special TF grease it goes away for a while than its back. It seems the grease keeps working out the back of the slip yoke via a little air hole. I have used numerous types of metal adherent greases to try and solve the problem but the clunk keep coming back after a month of driving or so.
What I need to know is if anybody else has had this problem?? The dealership told me to try another slip yoke(new one) and see what happens. I also heard that GM sells a grease product for a similiar problem they had with there 1500 series trucks.

What should I do......can anybody give me some advise. I love the truck but ready to sell if the problem persists!

thanx, D

 

I have found that a u-joint and slip yoke on a driveline going bad will quiet down when greased atleast for a while. Besides the clunk have you experienced some vibrations? How many miles do you have. If it is the slip yoke just grab it with both hands (eng. off of course) and try to twist and move up and down. If more than 1/8" movement it could be going bad. I don't know your driving style but Jackrabbit starts do put a load on the drivetrain.

 

The dealer is right about the teflon grease. It cushions the splines of the slip yoke and transmission output shaft.

Get yourself some teflon grease and really gob it in there or replace the slip yoke.

Ford Teflon Grease P/N D2AZ-19590-A It comes in a one pound can for $25.00 and has a beautiful turqouise hue

 

The truck has only got 90,000km(65,000mi) on her. I don't have any vibrations just the irritating clunk. I have used the Ford grease 3 times and keeps coming back. I think maybe changing the slip yoke will help????? I treat the truck like a BABY....99% street, but don't know how it was treated before I got her??
I will try greasing it one more time but man this is really starting to suck bad! Haven't checked the price on a new yoke, does anybody know the approx. cost of replacement? Guess I will ckeck monday morn.
Thanx guys, D

 

I have a 2000 f150 (118,000 km) with the same problem.I put some of fords teflon grease on the splines and it helped, but still clunks. Did you ever solve your problem? Did you ever replace your slip yolk, and if so, how much for the part?

 

i have a 97 with 110 000 kms on it, and i have the same problem, when your truck makes the clunking sound, if you have the 4x4 shifter on the floor, does it move with the clunk, on mine, when you here the cluk the shift moves backwards, i couldnt figure out what the problem was until i read these posts