| 1.   | I      have reviewed this annual report on Form 10-K, and all reports on Form 8-K      containing distribution or servicing reports filed in respect of periods      included in the year covered by this annual report of Navistar Financial      2006 Master Trust; |
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| 2.   | Based      on my knowledge, the information in these reports, taken as a whole, does      not contain any untrue statement of a material fact or omit to state a      material fact necessary to make the statements made, in light of the      circumstances under which such statements were made, not misleading as of      the last day of the period covered by this annual  report; |
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| 3.   | Based      on my knowledge, the distribution or servicing information required to be      provided to the trustee by the Servicer under the pooling and servicing      agreement, for inclusion in these reports, is included in these      reports; |
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| 4.   | Based      on my knowledge and upon the annual compliance statement included in the      report and required to be delivered to the trustee in accordance with the      terms of the pooling and servicing agreement, and except as disclosed in      the reports, the Servicer has fulfilled its obligations under that      agreement; and |
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| 5.   | The      reports disclose all instances of material non-compliance relating to the      Servicer's compliance with the minimum servicing standards based upon the      report provided by an independent public accountant, after conducting a      review in compliance with the requirements set forth in sections 3.02,      8.07 and Article IV of the Pooling and Servicing Agreement, that is      included in these reports.  |
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| 6.   | In      giving the certifications above, I have reasonably relied on information      provided to me by the following unaffiliated parties: Owner      Trustee. |
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| Date:        July 1, 2009 |                         By/s/: | DAVID      L. DERFELT      |
|-------------------------------------|--------------------------------------------------------------------------------------------------------------------------|----------------------------|
|                                |                                                                                                                     | David      L. Derfelt      |
|                                |                                                                                                                     | V.P.      & Controller |
|                                |                                                                                                                     |                       |

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