EXECUTION
      COPY


October
      23, 2007






425
      N.
      Martingale Road


Suite
      1800


Schaumburg,
      Illinois 60173




Re:  Waiver




Ladies/Gentlemen:




Please
      refer to (i) the Note Purchase Agreement, dated as of October 20, 2006 (as
      in
      effect on the date hereof, the "Note Purchase
      Agreement") among Navistar Financial Retail Receivables Corporation
      ("NFRRC"), as Seller, Navistar Financial Corporation, individually ("NFC")
      and
      as Servicer, Thunder Bay Funding, LLC, as Conduit Investor, and Royal Bank
      of
      Canada, as Agent and (ii) the Servicing Agreement, dated as of October 20,
      2006,
      among NFRRC, Navistar Financial 2006-RBC Owner Trust, as Issuer, NFC, as
      Servicer, and The Bank of New York, as Indenture Trustee. The Agent (on behalf
      of the Conduit Investor and the other Investors) is the holder of record of
      100%
      of the Floating Rate Asset Backed Note, No. R-1, issued by the Issuer pursuant
      to the Indenture. Capitalized terms used but not defined herein have the
      respective meanings ascribed to them (or incorporated by reference in) the
      Servicing Agreement.




The
      Note
      Purchase Agreement or the Servicing Agreement, as applicable, requires, among
      other things, the following:




(i)  Section
      5.02(c) of the Note Purchase Agreement requires that the Servicer deliver to
      the
      Agent (x) on or before July 31, 2007 (or earlier under certain circumstances
      specified therein), (x) a copy of the annual financial statements of the
      Servicer for the fiscal years October 31, 2005 and 2006 (each such delivery
      requirement, an "Annual Financial
      Statement
      DeliveryRequirement")
      and (y)
      (i) on or before July 31, 2007 (or earlier in certain circumstances specified
      therein), a copy of the quarterly financial statements of the Servicer for
      the
      fiscal quarters ended January 31, April 30 and July 31, 2006 and for the fiscal
      quarters ended January 31 and April 30, 2007 and (ii) on or before September
      15,
      2007 (i.e., within 45 days after the end of the July 31, 2007 fiscal quarter),
      a
      copy of the quarterly financial statements of the Servicer for the fiscal
      quarter ended July 31, 2007 (each such delivery requirement in this clause
      (y),
      a "Quarterly Financial
      Statement Delivery Requirement"); and




(ii)  Section
      3.02(a) of the Servicing Agreement requires that on or before July 31, 2007
      (or
      earlier under certain circumstances specified therein), the Servicer shall
      cause
      a firm of independent accountants to deliver to the Agent an independent
      Accountant's Report for the





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fiscal
      year ended October 31, 2006 (the "Independent Accountant's
      Report DeliveryRequirement").




The
      Servicer expects to fail to satisfy each Annual Financial Statement Delivery
      Requirement, each Quarterly Financial Statement Delivery Requirement and the
      Independent Accountant's Report Delivery Requirement.




Additionally,
      the Servicer has notified the Agent that it (i) has failed to timely file its
      annual reports on Form 10-K for the 2005 Fiscal Year and the 2006 Fiscal Year
      with the Securities and Exchange Commission in accordance with the Securities
      and Exchange Act of 1934, (ii) has failed to timely file quarterly reports
      on
      Form 10-Q for all of its fiscal quarters in 2006 with the Securities Exchange
      Commission in accordance with the Securities Exchange Act of 1934, and (iii)
      has
      failed to timely file one or more of its quarterly reports on Form 10-Q for
      fiscal quarters in 2007 with the Securities and Exchange Commission in
      accordance with the Securities and Exchange Act of 1934 (the occurrence of
      any
      such failure, a "Periodic Reporting
      Failure").




The
      Servicer has requested that the Agent waive any potential Servicer Defaults
      arising from the matters described above. The Agent hereby agrees to waive
      the
      occurrence of any Servicer Defaults to the extent described below.




1.  The
      Agent (in accordance with Section 7.06 of the Servicing Agreement) hereby
      directs the Indenture Trustee to waive, and each of Indenture Trustee, the
      Conduit Investor and the Agent hereby waives, any Servicer Default arising
      solely from the failure to satisfy the Annual Financial Statement Delivery
      Requirements; provided that this waiver shall only remain effective until
      December 31, 2007 unless the Servicer shall have satisfied each Annual Financial
      Statement Delivery Requirement prior to such date.




2.  The
      Agent (in accordance with Section 7.06 of the Servicing Agreement) hereby
      directs the Indenture Trustee to waive, and each of Indenture Trustee, the
      Conduit Investor and the Agent hereby waives, any Servicer Default arising
      solely from the failure to satisfy the Quarterly Financial Statement Delivery
      Requirements; provided that this waiver shall only remain effective until
      December 31, 2007 unless the Servicer shall have satisfied each Quarterly
      Financial Statement Delivery Requirement prior to such date.




3.  The
      Agent (in accordance with Section 7.06 of the Servicing Agreement) hereby
      directs the Indenture Trustee to waive, and each of Indenture Trustee, the
      Conduit Investor and the Agent hereby waives, any Servicer Default or default
      arising under Section 5.05 of the Note Purchase Agreement from any Periodic
      Reporting Failure; provided that this waiver shall only remain effective until
      December 31, 2007 unless the Servicer shall have caused the annual reports
      and
      quarterly reports giving rise to any Periodic Reporting Failure to be filed
      with
      the Securities and Exchange Commission prior to such date.


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4.  The
      Agent (in accordance with Section 7.06 of the Servicing Agreement) hereby
      directs the Indenture Trustee to waive, and each of Indenture Trustee and the
      Agent hereby waives, any Servicer Default arising solely from the failure of
      the
      Servicer to satisfy the Independent Accountant's Report Delivery Requirement;
      provided that this waiver shall only remain effective until December 31, 2007
      unless the Servicer shall have satisfied the Independent Accountant's Report
      Delivery Requirement prior to such date.




Each
      of
      the Indenture Trustee, the Conduit Investor and the Agent hereby expressly
      reserves, and nothing herein shall be construed as a waiver of, (i) any Servicer
      Default or default under the Note Purchase Agreement specified in paragraphs
      I,
      2, 3 and 4 above, to the extent that the effectiveness of the waiver of such
      Servicer Default or default under the Note Purchase Agreement shall lapse as
      described therein and (ii) any rights with respect to any breach constituting
      a
      Servicer Default, Potential Servicer Default or default under the Note Purchase
      Agreement existing or arising for any other reason.




This
      waiver may be executed in any number of counterparts and by the different
      parties on separate counterparts, and each such counterpart shall be deemed
      to
      be an original but all such counterparts shall together constitute one and
      the
      same waiver. This waiver shall be a contract made under and governed by the
      internal laws of the State of New York applicable to contracts made and to
      be
      performed entirely within such State.




E-411


IN
      WITNESS WHEREOF, the undersigned has caused this waiver to be duly executed
      and
      delivered by their respective duly authorized officers on the day and year
      first
      above written




ROYAL
      BANK OF CANADA, as Agent




By:           /s/ROGER
      PELLEGRINI


Name:           Roger
      Pelegrini


Title:            Authorized
      Signatory




THUNDER
      BAY FUNDING, LLC, as
      Conduit Investor


By:  Royal
      Bank of Canada its


its
      attorney-in-fact




By:           /s/ROGER
        PELLEGRINI
 Name:           Roger
        Pelegrini
 Title:            Authorized
        Signatory






THE
      BANK
      OF NEW YORK, not in its individual


capacity
      but solely as Indenture Trustee





By:        /s/MICHAEL
      BURACK


Name:        Michael Burack


Title            Assistant
      Treasurer




E-412




Acknowledged
      and Agreed:




NAVISTAR
      FINANCIAL CORPORATION




By:           /s/JOHN
      V.
      MULVANEY, SR.


Name:           John V.
      Mulvaney, Sr.


Title:            V.P.,
      CFO & Treasurer




NAVISTAR
      FINANCIAL RETAIL RECEIVABLES CORPORATION




By:           /s/JOHN
      V.
      MULVANEY, SR.


Name:           John V.
      Mulvaney, Sr.


Title:            V.P.,
      CFO & Treasurer




NAVISTAR
      FINANCIAL 2006-RBC OWNER TRUST


By:
      Deutsche Bank Trust Company Delaware, not in i


ts
      individual capacity, but solely as Owner Trustee




By:            /s/MICHELE
      HY VOON


Name:            Michele
      HY Voon


Title:              Attorney-in-fact




ROYAL
      BANK OF CANADA, as Swap Counterparty




By:           /s/ BRIAN
      OSMAR


Name              Brian
      Osmar


Title:               Senior
      Vice President


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