You should be able to adjust the metric setting for each interface, giving preference to the wired interface. By default, wired interfaces with a faster link speed should be given preference using the automatic metric setting. However, according to TechNet, automatic metric is usually enabled by default.
- Right-click a network interface, and then click Properties.
- Click Internet Protocol (TCP/IP), and then click Properties.
- On the General tab, click Advanced.
- To specify a metric, on the IP Settings tab, click to clear the Automatic metric check box, and then enter the metric that you want in the Interface Metric field.
(steps above adapted from KB299540)
A lower number represents a preferred interface, since the number represents a cost value for selecting that interface.