I have been having this Shudder in the Rear end..when i drive from a Stopped position i have to drive away real slow or my rear end will start to Shudder..I took it to the Ford Dealer Ship the other day and got some of that special friction additive put into the rear end..it made my Truck worse..now it sounds like metal Clanking when before it would just shudder..I have the Locked rear Differential in my 04 Ford f150 Fx4 4x4 as i was told by the mechanic...Could someone explain why its making the clanking noise now...

 

I have about the same problem in my 2003 fx4 .. I have a friend that has a f250 with the same problem , he said to call him Monday and he is going to tell me what I need to do .. So he says he fixed his.. I will find out Monday and post ..

 

thanks alot man...will be looking forward to your post..

 

Is it shuttering when you make a left or right turn from a dead stop? Did the mechanic change the fluid or did he just add the modifier? If he didn't drain the fluid that additive will not do its job. Mine was really "chattering" from a dead stop, espically when I was turning left or right. Read on here that sometimes a simple oil change in your diff. can work wonders. So I drained all the fluid out and added new fluid along with the friction modifier. So after 3 months I've had no chatter or grinding back there!!

 

There was no locking rear diff in 04 unless it was aftermarket. At best, you have a limited slip, which is why the friction modifier is needed. Only way to really tell what the problem is is to open it up.

 

thats what the mechanice at FORD was surprised about..that the truck has a locking rear end..when he turned one tire the other one turned as well in the same direction..he didnt swap out the old fluid..just poured in the additive..It mostly when i make a left turn from a dead stop that i will fell the shudder or now the clanking...

 

Turning in the same direction is also a sign of a limited slip. Nothing wrong with that, and does not mean you have a locking rear.

 

Change the fluid and add the friction modifier. If this does not fix it, you need a new clutch pack most likely.

MY 2000 9.75" rear with traction lok started chattering going around corners. New fluid and modifier did not fix it. Then I found out about a TSB on the subject. It said to replace the clutch pack and remove 0.010" worth of shims. The parts guy at the dealer said just add another bottle of modifier and that worked.

 

Just shudder can be cured with a fluid change and modifier - but clanking is something else entirely - that's a real problem.

 

X2...on a possible problem...might have problems with your spider gears...

 

Yes, if it is making a noise going straight, it ain't the traction lok clutches making the noise.