Ford f-150/ Vibration or shuddering

[95Road King]

I have a 04 Ford F-150 with 5.4 Triton engine.44,000 mi. right now. Had the limited slip worked on twice under warrenty. Lately out of the clear blue while driving along a vibration or shuddering will start. You'll swear you have a flat tire. Not so!! After stopping and checking things out and your back on the road, everything's ok!! Might go another 1000 mi. before it happens again!! I know it's in the rear end (Limited slip) cause I read about it in a car book. Only on 04 f-150's, and some cars. Forget warrenty, that's gone!!
    Anyone else have an 04 F-150 with this problem?? Did you do anything about it??

[quickdtoo]

Sounds like the diff needs a friction modifier additive to stop the chatter.  Dunno if it can just start chattering spontaneously, but it's a cheap fix if it works!!  It could also be a bad tie rod end or some other steering/suspension component that's wore out.

Tim

http://www.frsport.com/FR-Motorcraft-XL3-Limited-Slip-Differential-LSD-Friction-Modifier-Oil_p_2288.html

http://www.dieselfiltersonline.com/Xl-3-Motorcraft-Additive-Friction-Modifier-Xl-3.aspx

[PartsMan]

We have two FX4s about that age at work that shudder if you power through a corner.
I swore it was the limited slip.
Not so, the dealer "lubes the drive shaft" and it quits for a few hundred miles.
They pull the slip yoke apart and stuff grease in the female end. No lie!

[cotnpker]

THE FORD F-150 AND 250 HAVE AN INHERANT TORQUE CONVERTER PROBLEM. IT STARTS ABOUT 40,000 MILES AND THE ONLY FIX IS REPLACEMENT. MY SONS RAN ABOUT $800.00 TO HAVE IT REPLACED.  IT FEELS LIKE YOU ARE RUNNING ON A RUMBLE STRIP, BUT DOES NOT DO IT ALL THE TIME.

[95Road King]

Quick:
   Thanks for the info. The magazine article I spoke of mentioned some type of friction modifier. Next oil change I'll drain and put this stuff in and see what happens??

[Lloyd Smale]

faulty torque converter would have been my first guess too.

THE FORD F-150 AND 250 HAVE AN INHERANT TORQUE CONVERTER PROBLEM. IT STARTS ABOUT 40,000 MILES AND THE ONLY FIX IS REPLACEMENT. MY SONS RAN ABOUT $800.00 TO HAVE IT REPLACED.  IT FEELS LIKE YOU ARE RUNNING ON A RUMBLE STRIP, BUT DOES NOT DO IT ALL THE TIME.

[Longknife 76]

 I might vote for the converter also. My wife had a 95 ford mustang, at about 40 thou there would be a shudder when the Lockup conv. would go into overdrive. It felt like a bad u-joint. I changed the fluid and it stopped.... then I traded it in..Ed

[Longknife 76]

You could also try a can of tranny additive first?

[Bigeasy]

The limited slip in the rear end is a series of clutches that sometimes start to stick together, causing the problems you discribe.  Sometimes it comes and goes, and is worse in a low to moderate speen turn.  The fix is to add a special limited slip lubricant / additive, available at most auto supply shops.  I once had a Ford Ranger that was doing the same thing.  It was amazing the difference the additive made.

Larry