Hi everyone. I am new to this but am hopiong to get some help with an issue. I have a 2005 f150 XLT 5.4. So I guess iil just get to it. Whenever I go from a complete stop and begin to accelerate around a turn my rear end seems to vibrate. Had a mechanic take a quick look over it and he didn't see anything obvious and is worried it is somewhere in the defferential. Just looking for some direction. Im not afraid to take anything apart but really dont even know where to start. Let me know if anyone has any ideas. Thanks!

 

Well wish you got some replies as I have same issue, I will post my findings. Good luck.

 

Sounds like you need to add some friction modifier to your differential. Do you know if it's limited slip or not and the last time it was serviced?

 

I don't know if limited slip, find out tomorrow just bought truck not long ago and don't believe he did much servicing. I can pull rear cover and drain, what amount and kind oil to use on high miles, it just started this a bit ago. What is friction modifiers......thx

 

You need to look inside the door jamb and post your "axle code" that will tell us if its limited slil and what kind of weight oil.

 

I would try a diffy service.

 

Where it says axle under it B6

 

You have. 3.73 lSD you nedd to pull cover snd drain and refill with

Rear diff 3 quarts of 75w-140 synthetic with 8 oz of friction modifer xl-3


The xl-3 limited slip addtive shoulf clear up thr chaddering u hear
. Be sure to do a few figure 8s too

 

Ok perfect will do it tomorrow, will new gaskit work or will need tube of gaskit maker, thx a lot guys.

 

So do I have limited slip rear end?