Section 7 (Steering System): Operation: Operation
WARNING: This page is about a different car, the 2012 Jeep Wrangler. However, it is still accessible from the selected car via links, so may be relevant.
The gear acts as a rolling thread between the worm shaft and rack piston. The worm shaft is supported by a thrust bearing at the upper end. When the worm shaft is turned from input from the steering column the rack piston moves. The rack piston teeth mesh with the pitman shaft. Turning the worm shaft turns the pitman shaft, which turns the steering linkage.