HI I'm new here and a new owner of a 2004 f150 4x4 4.6 V8. Currently has 140,000 mi. I'm looking for some possibilities to check on a rear vibration when starting from a stop, turning, and backing up. Its not a violent vibration but a subtle one but you can feel it and its annoying. This just started recently. Other than that it rides and drives nicely. I'm looking for some advice on what things I could check to find the problem. Has anyone out there had any experiences with this?

Thanks for any help given
Terry

 

Limited slip differential clutch chatter. Check your door jamb sticker for the AXLE code - if it starts with a letter (i.e. H9) it's limited slip.

Change the diff lube - it takes 75W140 synthetic (any brand), and add one bottle of Ford friction modifier (from the dealer). The cover has to come off to drain the fluid (make sure you can get the fill plug loose before removing the cover!!!) and you can use either a gasket or RTV to reseal the cover.

 

I highly recommend using a diff cover gasket. If you don't get the RTV exactly right, it will leak.

 

A ton of thanks for the advice to you both! I had a gut feeling thats what it was. I will get this checked out. What would the cost be to get this fixed?

 

3 qts of 75w140 synthetic lube at $9 to $12 qt, 1 bottle of friction modifier from Ford- $8 or so, gasket less than $10 I believe at an auto parts store is what it will cost if you do it. Add $100 if a shop does it, $150 is the dealer does it. Just estimating.

If you do it make sure you can get the fill plug out before you take the cover off to get the lube drained. When refilling, I use a piece of tygon tubing on the snout of one of the bottles to make the refill easy.

 

I just ordered Ford friction modifier from Amazon and I'm going to add it to the existing lube and forget it. $6.99 delivered to my door.

 

I personally like refilling by pouring in from the ABS sensor up top (with the fill plug removed)

 

So thats how a differential clutch chatter is fixed? I hope thats all there is to it. What are the signs it could be the U-joint? After talking with my son he said it sounded like a U-joint problem like he had.
What are your thoughts on this?

 

Thanks for the info Osbornk. Sounds like a great deal. If I do need this thats what I'll do too