Q: So this shop just put some oil in my rear differential and now it's making a grinding noise? What could be causing that?

Hi Elishea. Thanks for contacting us today. Generally speaking, the rear differential has no impact on the steering of the vehicle, so it’s quite possible that adding the fluid to the rear differential is not the source of this noise. Typically a grinding noise like you’ve described would be caused by damage to the steering box or other steering and suspension components. I would recommend contacting the service shop that completed this to report the symptom to them, and ask if any other service was completed without your knowledge or perhaps the vehicle was raised on a hydraulic lift incorrectly. In any case, it’s best to give them the opportunity to resolve this issue first before getting another mechanic or shop involved.