<PAGE>

                                                                   EXHIBIT 10.22


                      TRANSLATION FROM THE GERMAN LANGUAGE


                          SHARE PURCHASE AGREEMENT(1)

                               (THE "AGREEMENT")

                                11 JANUARY 2002

                                    between

      1.    BRENNERO TRASPORTO ROTAIA S.P.A., Brennerstrasse 7, I-39100 Bozen,
            Italy ("STR"),

      2.    BIMODAL VERWALTUNGS GESELLSCHAFT MBH, Rhondorfer Strasse 85, D-53604
            Bad Honnef, Germany ("BIMODAL"),

      (collectively the "PURCHASERS")

                                      and

      3.    WABASH NATIONAL CORPORATION, 1000 Sagamore Parkway South, Lafayette.
            Indiana 47905, U.S.A. ("WABASH" or the "SELLER").

The Purchasers and the Seller, as the case may be, each are referred to herein
as a "PARTY" and collectively as the "PARTIES".


----------

(1)   This Agreement has to be executed in the form of a German notarial deed.
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                      TRANSLATION FROM THE GERMAN LANGUAGE


WHEREAS

(1)   The Company is a company with limited liability under German law, with its
      registered seat in Munich, Germany, registered under the registration
      number HRB 10642 in the Commercial Register Munich with a fully paid up
      nominal share capital of DEM 17,357,000,-- (in words: German Mark
      seventeen million three hundred fifty-seven thousand).

(2)   STR is a joint stock corporation under Italian law registered under
      registration number 01667390213 in the Commercial Register Bozen, Italy
      and having its commercial seat in Bozen, Italy.

(3)   Bimodal is a company with limited liability under German law which until
      present had been registered in the commercial register of the District
      Court of Frankfurt (Amtsgericht Frankfurt) under registration number HRB
      53240 under the name of "Blitz F01-901 GmbH", which had had its registered
      seat in Frankfurt/Main and the name of which has been changed to "Bimodal
      Verwaltungs GmbH" by a shareholders' resolution certified by a notary
      public, but not registered so far and the seat of which has been
      transferred to Bad Honnef.

(4)   The Seller is a corporation under the laws of Delaware, with its
      registered seat in Lafayette, Indiana, U.S.A., owning 100% of the shares
      (Geschaftsanteile) in the Company (the "SHARES").

(5)   As of this date, the Seller and the Purchasers have concluded a Framework
      Agreement (the "FRAMEWORK AGREEMENT"). In execution of the respective
      terms and conditions of the Framework Agreement the Seller wishes to sell
      and transfer, and the Purchasers together wish to purchase and acquire
      100% of the Shares in the Company representing the entire nominal share
      capital of the Company under the terms and conditions of this Agreement.
      STR wishes to purchase 49% of the Shares and Bimodal wishes to purchase
      51% of the Shares.

NOW, THEREFORE, in consideration of the mutual promises made herein and the
mutual benefits to be derived form this Agreement, and in execution of the
Framework Agreement the Parties hereto agree as follows:

                                   ARTICLE I
                                  DEFINITIONS

Except if expressly defined otherwise in this Agreement, the defined terms in
this Agreement shall have the same meaning as in the Framework Agreement entered
into between the Parties as of this date (the "FRAMEWORK AGREEMENT"). The
defined terms in this Agreement shall have the meaning as set out below:


                                                                               2
<PAGE>
                      TRANSLATION FROM THE GERMAN LANGUAGE


<TABLE>
<S>                         <C>
AGREEMENT                   This Share Purchase Agreement.

FRAMEWORK AGREEMENT         The Framework Agreement between Wabash, STR and
                            Bimodal as of this date.

PURCHASE PRICE              The Purchase Price for all the Shares in the Company
                            pursuant to Article III.
</TABLE>


                                   ARTICLE II
                          SALE AND TRANSFER OF SHARES

(1)   The Seller as the sole shareholder of ETZ, waiving any and all
      requirements in terms of form and time of a shareholders' meeting, hereby
      resolves to pool all shares of ETZ into one single share of the nominal
      value of DEM 17,357,000.00.

(2)   For the purpose of transfer pursuant to Paragraph 3, the Seller hereby
      divides the share of ETZ of the nominal value of DEM 17,357,000.00 into
      one share of the nominal value of DEM 8,852,160.00 and into one share of
      the nominal value of DEM 8,504,960.00. The Seller as the sole shareholder
      of ETZ, waiving all requirements in terms of form and time of a
      shareholders' meeting, hereby resolves that the division pursuant the
      first sentence shall be agreed upon.

(3)   The seller sells and transfers to Bimodal, which accepts this, a share of
      a nominal value of DEM 8,852,160.00. The Seller sells and transfers to
      STR, which accepts this, a share of a nominal value of DEM 8,504,960.00.

(4)   The Seller as the sole shareholder of ETZ, waiving any and all
      requirements in terms of form and time of a shareholders' meeting, that
      the transfer of shares pursuant to Paragraph 3 shall be agreed upon.

(5)   The transfer of shares pursuant to Paragraph 3 shall be effective upon
      the effectiveness of the Framework Agreement.

(6)   The transfer of shares pursuant to Paragraph 3 shall become effective on
      the basis of the law of obligations (schuldrechliche Wirkung) as of
      January 1, 2002, including any and all corresponding dividends
      (Gewinnbezugsrecht), irrespective of the fact that they were distributed
      or not.

                                  ARTICLE III
                                 PURCHASE PRICE

(1)   The purchase price for the Shares sold pursuant to Article II (1) above
      shall be in the amount of (euro) 1.-- (in words: Euro one) (the "PURCHASE
      PRICE").

(2)   The Purchase Price shall be due on the date of this Agreement and shall
      jointly be paid by the Purchasers to the Seller free of any charges and
      fees.


                                                                               3
<PAGE>
                      TRANSLATION FROM THE GERMAN LANGUAGE


                                   ARTICLE IV
                          EXCLUSION OF FURTHER CLAIMS

    UNLESS OTHERWISE PROVIDED FOR IN EXPRESS TERMS IN THIS AGREEMENT OR THE
 FRAMEWORK AGREEMENT, THE PROVISIONS OF THE FRAMEWORK AGREEMENT SHALL APPLY IN
         TERMS OF THE TYPE AND SCOPE OF LIABILITY UNDER THIS AGREEMENT.

                                   ARTICLE V
                                CONFIDENTIALITY

(1)   The Parties agree that the existence and substance of this Agreement,
      including all Annexes thereto, shall remain confidential and,
      notwithstanding the requirements of mandatory law, shall not be announced
      or otherwise disclosed without the prior written consent of the other
      Party.

(2)   All communications, especially to the media, to customers, to suppliers,
      distributors, or authorized dealers shall be agreed upon in advance by the
      Parties.

(3)   This obligation of confidentiality shall not apply to information that is
      generally available to the public, or is required to be disclosed by law,
      court order or request by any governmental or regulatory authority.

                                   ARTICLE VI
                                COSTS AND TAXES

(1)   All costs resulting from negotiation and drafting of this Agreement,
      including but not limited to fees charged by legal, accountancy and
      financial advisors, shall be borne by such Party where they occurred and
      shall not be reimbursable by the other Party or the Company.

(2)   The Purchaser and the Seller shall respectively bear 50% of any transfer
      and sales taxes and fees, including but not limited to, notarial fees in
      connection with this Agreement.

                                  ARTICLE VII
                               GENERAL PROVISIONS

(1)   This Agreement and the Framework Agreement including its Annexes contain
      the entire agreement between the Parties relating to the transaction
      contemplated by this Agreement and supersede and replace any previous
      agreements between the Parties relating to this transaction. Each of the
      Parties acknowledges that in agreeing to enter into this Agreement it has
      not relied on any representation, warranty or other assurance except as
      expressly set out in this Agreement or the Framework Agreement.


                                                                               4
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                      TRANSLATION FROM THE GERMAN LANGUAGE


(2)   The Article and Section headings contained in this Agreement are solely
      for the purpose of reference, are not of the agreement between the Parties
      and shall not in any way affect the meaning or construction of this
      Agreement.

(3)   This Agreement shall not be amended orally and shall not be amended or
      discharged in whole or in part, otherwise than by an instrument in writing
      signed by the Parties or their successors or their assignees.

(4)   If one or several provisions of this Agreement should be or become invalid
      or unenforceable, the remaining provisions hereof shall not be affected
      thereby. The invalid or unenforceable provision shall be deemed to be
      replaced by such valid or enforceable provision as the Parties hereto
      would have chosen upon entering into this Agreement in order to reach the
      commercial effect of the provision to be replaced if they had foreseen the
      invalidity or unenforceability at the time of the conclusion of this
      Agreement. The foregoing shall also apply to matters as to which this
      Agreement is silent (Lucke am Vertrag). If a provision of this Agreement
      should be held invalid by a competent court or arbitration tribunal
      because of the scope of its coverage (such as territory, subject matter,
      time period or amount), said provision shall not be deemed to be
      completely invalid but shall be deemed to be valid with the permissible
      scope that is nearest to the scope originally agreed upon.

(5)   Except as otherwise provided in this Agreement, any failure of any of the
      Parties to comply with any obligation, covenant, agreement or condition of
      this Agreement may be waived by the Party or Parties entitled to the
      benefits thereof only by a written instrument signed by the Party granting
      such waiver, but such waiver or failure to insist upon strict compliance
      with any such obligation, covenant, agreement or condition shall not be
      deemed a waiver of any other obligation, covenant, agreement or condition
      or any subsequent or other failure. IWhenever this Agreement requires or
      permits consent by or on behalf of any Party hereto, such consent shall be
      given in writing in a manner consistent with the requirements for a waiver
      of compliance as set forth herein.

(6)   This Agreement has been produced in the German language; any
      translations thereof are for working purposes only and shall have no
      influence on the interpretation of the Agreement.

(7)   Neither this Agreement nor any of the rights, interests or obligations
      hereunder shall be susceptible of assignment by any of the Parties hereto
      without the prior written consent of the other Party.

(8)   All notices under this Agreement shall be in writing and shall be sent to
      the following addresses per registered or certified mail or by confirmed
      facsimile transmission:

       For the Seller:

       WABASH National Corporation,      Tel: +7657715300
       1000 Sagamore Parkway South,      email: rich.dessimoz@wabashnational.com
       Lafayette, Indiana 47905, U.S.A.
       Attn.: Rich Dessimoz


                                                                               5
<PAGE>
                      TRANSLATION FROM THE GERMAN LANGUAGE


       For STR:

       Brennero Trasporto Rotoia S.p.A.  Tel.: [...]
       Brennerstrasse 7, I-39100 Bozen,  Fax.: [...]
       Italy                             Email: [...]
       Attn.: [...]

       For Bimodal:

       Bimodal Verwaltungs
       Gesellschaft                      Tel.: [...]
       mbH, Rhondorfer Strasse 85,
       D-53604                           Fax.: [...]
       Bad Honnef, Germany               Email: [...]
       Attn.: [...]

      All such notices shall he deemed received upon (i) actual receipt thereof
      by the addressee, (ii) actual delivery thereof to the appropriate address
      or (iii) in the case of a facsimile transmission, upon transmission
      thereof by the sender and by return facsimile by the addressee confirming
      that the number of pages constituting the notice have been received
      without error. In the case of notices sent by facsimile transmission, the
      sender shall contemporaneously send a copy of the notice by registered
      mail to the addressee at the address provided for above. However, such
      mailing, shall in no way alter the time at which the facsimile notice is
      deemed received.

                                  ARTICLE VIII
                                 APPLICABLE LAW

(1)   This Agreement shall be governed by and construed in accordance with the
      laws of Germany, without giving effect to the principles of conflicts of
      law thereof. The application of the United Nations Convention on Contracts
      for the International Sale of Goods shall expressly be excluded.

(2)   The courts of Munich shall have exclusive jurisdiction to decide on all
      litigations arising under and in connection with this Agreement including
      all its Annexes.

(3)   The Agreement has to be executed in the way the Framework Agreement is
      executed.

                  [Reminder of page intentionally left blank]


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<PAGE>
                      TRANSLATION FROM THE GERMAN LANGUAGE


Munich, 11 January 2002


                                  ON BEHALF OF
                                   THE SELLER


_____________________________                    _______________________________
           [...]                                             [...]


                                  ON BEHALF OF
                                      STR


_____________________________                    _______________________________
           [...]                                             [...]


                                  ON BEHALF OF
                                    BIMODAL


_____________________________                    _______________________________
           [...]                                             [...]


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