BMW Steering Gear Goes Thump
This bulletin applies to 2016 BMW 2-series, 3-series and 4-series vehicles. If a thumping noise is heard from the front axle during slow speed turning, the noise most typically occurs at ambient temperatures above 75 degrees F and at normal engine operating temperature. Note that only vehicles equipped with the manufacturer Zahnradfabrik Friedrichshafen (ZF) standard steering gear are affected.
The issue does not affect gears made by Thyssen-Krupp (TKPS). Only those steering gears equipped with tie rods made by CTR have been found to have possible corrosion on the inside tie rod joint. If you verify that the steering gear is made by ZF, pull the rack bellows boot back to determine the manufacturer of the inner tie rod. If the tie rod is made by CTR, inspect to see if the grease is discolored and if corrosion is found on the joint.
To correct the issue, replace the tie rod(s). Replacement inner tie rods are available as P/N 32 10 6 799 960 for the left tie rod and 32 10 6 799 965 for the right tie rod.