X0306 4 2019-05-08 1 0001411207 Allison Transmission Holdings Inc ALSN 0001349666 Harker William R C/O ALLISON TRANSMISSION HOLDINGS INC. ONE ALLISON WAY INDIANAPOLIS IN 46222 1 0 0 0 Common Stock 2019-05-09 4 M 0 10318 0 A 10318 D Common Stock 2019-05-09 4 S 0 4977043 46.70 D 4977042 I See Footnote Deferred Stock Units 2019-05-08 4 A 0 537 0 A Common Stock 537 10162 D Deferred Stock Units 2019-05-09 4 M 0 10162 0 D Common Stock 10162 0 D Divided Equivalents 2019-05-09 4 M 0 156 0 D Common Stock 156 0 D Represents the deferred stock units ("DSUs") payable upon the reporting person's separation from service. The reporting person resigned from Allison Transmission Holdings, Inc.'s (the "Company") Board of Directors on May 9, 2019. Includes 10,162 DSUs and 156 related dividend equivalents. These shares are beneficially owned by Ashe Capital Management, LP ("Ashe Capital"). Ashe Capital is a registered investment adviser and acts as an investment adviser to various private investment limited partnerships. The reporting person is a member of Ashe GP, LLC, which is Ashe Capital's general partner. The reporting person disclaims beneficial ownership of these shares except to the extent of his pecuniary interest therein. These DSUs represent a quarterly payment of the portion of the reporting person's annual retainer and other fees under the Company's Fifth 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 and other fees are 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 $45.36, which was the closing price of the Company's common stock on the date of grant. Each dividend equivalent right is the economic equivalent of one share of the Company's common stock. The dividend equivalent rights accrued on previously awarded DSUs and were payable on May 9, 2019, the date of the reporting person's separation from service. /s/ Jacalyn C. Bolles, Attorney-in-Fact 2019-05-10