X0508 4/A 2018-08-10 2018-08-14 0001411207 Allison Transmission Holdings Inc ALSN 0001171774 LAVIN RICHARD P C/O ALLISON TRANSMISSION HOLDINGS, INC. ONE ALLISON WAY INDIANAPOLIS IN 46222 1 0 0 0 0 Deferred Stock Units 2018-08-10 4 A 0 477 0 A Common Stock 477 29696 D The reporting person is filing this amendment to the Form 4 originally filed on August 14, 2018, as well as amendments to the Form 4s originally filed on November 14, 2018 and February 13, 2019, solely to reflect that the annual retainer awards reported in such Form 4s were granted to the reporting person in the form of deferred stock units ("DSUs") and not common stock. The subsequent Form 4s filed by the reporting person overstated the reporting person's direct holdings of common stock by an aggregate of 1,414 shares. As of March 28, 2024, the date of this amendment, the reporting person directly holds 9,826 shares of common stock. These DSUs represent a quarterly payment of the portion of the reporting person's annual retainer under the Allison Transmission Holdings, Inc. (the "Company") Third Amended and Restated Non-Employee Director Compensation Policy deferred pursuant to the Company's Amended and Restated Non-Employee Director Deferred Compensation Plan. The annual retainer is payable quarterly in arrears. Each DSU is the economic equivalent of one share of the Company's common stock. The DSUs become payable, in common stock, or at the Company's election cash, at the earlier of the reporting person's separation from service or a change in control. DSUs earn dividend equivalents when dividends are declared on the Company's common stock. The number of DSUs received was calculated based on $45.82, which was the closing price of the Company's common stock on the date of grant. Represents the total number of DSUs held by the reporting person as of March 28, 2024, the date of this amendment, and reflects all transactions through such date. /s/ Preston B. Ray, attorney-in-fact 2024-03-28