UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ Quarterly Report Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 For the quarterly period ended September 30, 2023 OR ☐ Transition Report Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 For the transition period from to Commission File No. 001-14817 PACCAR Inc (Exact name of registrant as specified in its charter) Delaware 91-0351110 (State or other jurisdiction of (I.R.S. Employ ...