PACCAR INC

The proxy form allows registered stockholders to vote in one of three ways:

Mail. Stockholders may complete, sign, date and return the proxy form in the pre-addressed, postage-paid envelope provided.

Telephone. Stockholders may call the toll-free number listed on the proxy form and follow the voting instructions given.

Internet. Stockholders may access the internet address listed on the proxy form and follow the voting instructions given.

Telephone and internet voting procedures authenticate each stockholder by using a control number. The voting procedures will confirm that your instructions have been properly recorded. Stockholders who vote by telephone or internet should not return the proxy form.

Stockholders who hold shares through a broker or agent should follow the voting instructions received from that broker or agent.

Revoking Proxy Voting Instructions. A proxy may be revoked by a later-dated proxy or by written notice to the Secretary of the Company at any time before it is voted. Stockholders who hold shares through a broker should contact the broker or other agent if they wish to change their vote after executing the proxy.