I have a 2005 f150 4x4. it makes a strange shudder every time i turn from a stop sign or use the accelerator when turning. i have been told that it may be something to do with the diff, but i am not sure. i think this truck has a lsd. the axle code is b6. any help or insight would be much appreciated.

 

It is easy to change the diff gear oil. Just make sure to use the type for limited slip. Your rearend should have a tag that says limited slip if it has it, assuming it has not been removed.

It will not hurt to use limited slip gear oil in yours even if it does not have it. The limited slip additive just helps the clutches inside the limited slip to slide over each other and not grab. That is what your shudder could be, the clutches not sliding smoothly.