Hello, I have noticed on my.

Hello,

I have noticed on my mountaineer (AWD-V8-117k) that sometimes when I accelerate. Mostly going 35 mph+ I get a "slight" jerk that sounds like it may be coming from the rear end. It only happens intermittently when I let off the gas, then press on it. The car shifts just fine so not a tranny issue but what about the rear differential? Is it typical or normal? Or could the fluid be bad causing this? Like I said, it's not like it SLAMS but there's that slight jerk I can feel.