FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN 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

OMB APPROVAL OMB Number: 3235-0287 Expires: January 31, 2005 Estimated average burden hours per response... 0.5

(Print or Type Responses)

1. Name and Address of Reporting Person * CAISSE DE DEPOT ET PLACEMENT DU QUEBEC   2. Issuer Name and Ticker or Trading Symbol Altra Holdings, Inc. [AIMC] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director __X__ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 1000 PLACE JEAN-PAUL RIOPELLE 3. Date of Earliest Transaction (Month/Day/Year) 12/20/2006 (Street) MONTREAL, A8 H2Z 2B3 4. If Amendment, Date Original Filed(Month/Day/Year) 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 Acquired, Disposed of, or Beneficially Owned

1.Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock (1) 12/20/2006   J   0 A $ 0 3,500,000 D (2)   Preferred Stock (1) 12/20/2006   J   0 D $ 0 0 D (2)   Common Stock 12/20/2006   S   1,346,391 D $ 13.5 2,153,609 D (2)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
	Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number.		SEC 1474 (9-02)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

4. Transaction Code (Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5)

6. Date Exercisable and Expiration Date (Month/Day/Year)

7. Title and Amount of Underlying Securities (Instr. 3 and 4)

8. Price of Derivative Security (Instr. 5)

9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

Code

V

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
CAISSE DE DEPOT ET PLACEMENT DU QUEBEC 1000 PLACE JEAN-PAUL RIOPELLE MONTREAL, A8 H2Z 2B3		X
HOULE LUC 1000 PLACE JEAN-PAUL RIOPELLE MONTREAL, A8 H2Z 2B3		X
LALONDE LOUISE 1000 PLACE JEAN-PAUL RIOPELLE MONTREAL, A8 H2Z 2B3		X

Signatures

/s/ Paule Gaumond, Attorney-In-Fact for Caisse de Depot et Placement du Quebec, Louise Lalonde and Luc Houle		12/20/2006
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 4(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)	Upon the closing of the initial public offering of the Issuer's Common Stock on 12/20/2006, all outstanding shares of Preferred Stock were automatically converted into shares of the Issuer's Common Stock on a one share of Common Stock for every two shares of Preferred Stock outstanding basis.
(2)	Because Louise Lalonde and Luc Houle exercise voting and investment control over the shares of Altra Holdings, Inc. held by Caisse de Depot et Placement du Quebec, they may be deemed to be the beneficial owners of shares deemed to be beneficially owned by such entity. Each of Louise Lalonde and Luc Houle disclaim beneficial ownership of these shares, except to the extent of any pecuniary interest therein. Exhibit List: Exhibit 24 - Power of Attorney; Exhibit 99- Joint Filer Information

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.

Potential persons who are to respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB number.