When i put the truck in reverse and start driving the i hear a single clunk after driving 8 feet and then nothing else. It sounds like it is coming from the rear axle but i don't know if it's the diff or not. Any ideas? Hopefully it's just the gears in the rearend, i have the new parts all ready to go in anyways

-Jon

 

I have the same exact problem and I dont know what is causing it. I have a 2000 F150 supercab 4X$ 5.4L. Any guesses anyone?

 

If you have a 4x4, when was the last time you changed your transfer case fluid?

that long hunh?

Change it and use a good MERCON V fluid. I believe in Amsoil in the transfer case (only need two quarts). Royal Purple may be another good one.

If you have a 2x4, then I would suggest putting the rear end on jack stands, put the tranny in neutral and give the rear u-joint a shake. Look for excessive play in the pinion (rear-end side of the rear u-joint).

 

how hard ir it to change the transfer case fluid how often should it be done any websight showing how to do it

 

It is a 4X4. I changed my differential fluid last fall with royal purple but god only knows the last time the transfer case fluid has been changed, if ever. I am going to try and find out what kind of royal purple I will need.

 

I had that problem in an older truck and it was the u-joints.

 

Do I have to get the rear axle on jack stands to check the U-joints? What do I do when I check them and where am I looking for movement?

thanks

 

If I were a betting man, I would say you have nothing to worry about. In the late model p-ups for some reason Ford designed the rear ends with an unusual amount of slack. It is often common to hear an initial "clunk" when shifting into reverse.

 

I believe that the recommended change interval for the transfer case fluid is 30,000 miles.

Changing is easy! there is a plug on the bottom (3/8 ratchet to remove) and one on the back (just like the rear end).

Pull the plug and catch the fluid. then, put the bottom plug in and fill through the back plug until fluid reaches the fill hole. Install the rear plug and you are done.

Be sure to verify what fluid is required in your vehicle. my 2000 and 2002 both required MERCON V. I used Amsoil (personal preference).