Ownership Submission
FORM 3
 UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
  ONEX CORP
 2. Date of Event Requiring Statement (Month/Day/Year)
03/14/2012		 3. Issuer Name and Ticker or Trading Symbol
Allison Transmission Holdings Inc [ALSN]
(Last)
(First)
(Middle)
C/O ONEX CORPORATION, 161 BAY STREET		 4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director __X__ 10% Owner
_____ Officer (give title below) _____ Other (specify below)
5. If Amendment, Date Original Filed(Month/Day/Year)
(Street)

TORONTO, A6 M5J 2S1		 6. Individual or Joint/Group Filing(Check Applicable Line)
___ Form filed by One Reporting Person
_X_ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Beneficially Owned
1.Title of Security
(Instr. 4)		 2. Amount of Securities Beneficially Owned
(Instr. 4)		 3. Ownership Form: Direct (D) or Indirect (I)
(Instr. 5)		 4. Nature of Indirect Beneficial Ownership
(Instr. 5)
Common Stock 90,356,249
I
See Footnotes (1) (2) (3) (4) (5)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 4)		 2. Date Exercisable and Expiration Date
(Month/Day/Year)		 3. Title and Amount of Securities Underlying Derivative Security
(Instr. 4)		 4. Conversion or Exercise Price of Derivative Security 5. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 5)		 6. Nature of Indirect Beneficial Ownership
(Instr. 5)
Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
ONEX CORP
C/O ONEX CORPORATION
161 BAY STREET
TORONTO, A6 M5J 2S1		     X    
SCHWARTZ GERALD W
C/O ONEX CORPORATION
161 BAY STREET
TORONTO, A6 M5J 2S1		     X    
Onex American Holdings II LLC
C/O ONEX CORPORATION
161 BAY STREET
TORONTO, A6 M5J 2S1		     X    
Onex American Holdings GP LLC
C/O ONEX CORPORATION
161 BAY STREET
TORONTO, A6 M5J 2S1		     X    
Allison Executive Investco LLC
C/O ONEX CORPORATION
161 BAY STREET
TORONTO, A6 M5J 2S1		     X    
Allison Executive Investco II LLC
C/O ONEX CORPORATION
161 BAY STREET
TORONTO, A6 M5J 2S1		     X    
Onex American Holdings Subco LLC
C/O ONEX CORPORATION
161 BAY STREET
TORONTO, A6 M5J 2S1		     X    
OAH Wind LLC
C/O ONEX CORPORATION
161 BAY STREET
TORONTO, A6 M5J 2S1		     X    
Onex Allison Holding Ltd S.A.R.L.
C/O ONEX CORPORATION
161 BAY STREET
TORONTO, A6 M5J 2S1		     X    

Signatures

/s/ Christopher Govan, Authorized Person 03/14/2012
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 5(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) Includes: (i) 40,849,245 shares of common stock held by Onex Partners II LP; (ii) 25,949,370 shares of common stock held by Onex American Holdings II LLC; (iii) 383,940 shares of common stock held by Onex Partners II GP LP; (iv) 769,558 shares of common stock held by Onex US Principals LP; (v) 19,256,250 shares of common stock held by Onex Allison Co-Invest LP; and (vi) 1,513,297 shares of common stock held by Allison Executive Investco LLC.
(2) Onex Corporation may be deemed to beneficially own the common stock held by (a) Onex Partners II LP, through Onex Corporation's ownership of all of the common stock of Onex Partners GP Inc., the general partner of Onex Partners II GP LP, the general partner of Onex Partners II LP, (b) Onex American Holdings II LLC, through Onex Corporation's ownership of all of the equity of Onex American Holdings II LLC, (c) Onex Partners II GP LP, through Onex Corporation's ownership of all of the common stock of Onex Partners GP Inc., the general partner of Onex Partners II GP LP, (continued)
(3) (d) Onex US Principals LP, through Onex Corporation's ownership of all of the equity of Onex American Holdings II LLC, which owns all of the equity of Onex American Holdings GP LLC, the general partner of Onex US Principals LP, (e) Onex Allison Co-Invest LP, through Onex Corporation's ownership of all of the common stock of Onex Partners GP Inc., the general partner of Onex Partners II GP LP, the general partner of Onex Allison Co-Invest LP, and (f) Allison Executive Investco LLC, through Onex Corporation's ownership of all of the equity of Onex American Holdings II LLC, which owns all of the equity of Allison Executive Investco LLC.
(4) Also includes 1,633,404 shares of common stock and 1,185 shares of non-voting common stock held by Onex Advisor III LLC, an independent entity that is controlled by Mr. Gerald W. Schwartz. Mr. Schwartz, the Chairman, President and Chief Executive Officer of Onex Corporation, owns shares representing a majority of the voting rights of the shares of Onex Corporation and as such may be deemed to own beneficially all of the common stock and non-voting common stock owned beneficially by Onex Corporation. Mr. Schwartz disclaims such beneficial ownership, except to the extent of his pecuniary interest therein. Mr. Schwartz has indirect voting and investment control of Onex Corporation.
(5) Due to the limitations of the electronic filing system, Onex Partners LLC, Onex US Principals LP, Onex Partners GP Inc., Onex Partners II GP LP, Onex Allison Co-Invest LP, Onex Partners II LP, 1597257 Ontario Inc., Onex Advisor III LLC and Onex Advisor Subco LLC are filing a separate Form 3.
 
Remarks:
Exhibit List:

Exhibit 99 - Joint Filer Information

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