EXHIBIT 12.3 PACCAR Inc COMPUTATION OF RATIO OF EARNINGS TO FIXED CHARGES PURSUANT TO SEC REPORTING REQUIREMENTS (Thousands of Dollars) Nine Months Ended September 30 1997 1996 - - -------------------------------------------------------------------------------- FIXED CHARGES Interest expense PACCAR Inc and subsidiaries (1) $108,695 $ 97,487 Portion of rentals deemed interest 4,579 4,414 - - -------------------------------------------------------------------------------- TOTAL FIXED CHARGES $113,274 $101,901 - - -------------------------------------------------------------------------------- EARNINGS Income before taxes- PACCAR Inc and subsidiaries $327,524 $219,168 Fixed charges 113,274 101,901 - - -------------------------------------------------------------------------------- EARNINGS AS DEFINED $440,798 $321,069 - - -------------------------------------------------------------------------------- RATIO OF EARNINGS TO FIXED CHARGES 3.89X 3.15X - - -------------------------------------------------------------------------------- (1) Exclusive of interest, if any, paid to PACCAR Inc. 12