               UNITED STATES SECURITIES AND EXCHANGE COMMISSION
                             Washington, D. C. 20549


                                    FORM 8-K


                                 CURRENT REPORT
                       Pursuant to Section 13 or 15(d) of
                       the Securities Exchange Act of 1934



         Date of Report (Date of earliest event reported) MayJune 1615, 2005


                     NAVISTAR FINANCIAL 2003-B OWNER TRUST
             (Exact name of Registrant as specified in its charter)


                                    Delaware
                 (State or other jurisdiction of incorporation)



              333-67112-05                           32-6027547
      (Commission File Number)            (I.R.S. Employer Identification No.)




  425 N. Martingale Road Schaumburg, Illinois              60173
   (Address of principal executive offices)             (Zip Code)



         Registrant's telephone number including area code 630-753-4000


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                    INFORMATION TO BE INCLUDED IN THE REPORT


Item 8.01  Other Events.


           On MayJune 1615, 2005, the Registrant made available the
           Monthly Servicer Certificate for the Period of AprilMay 2005
           for the NAVISTAR FINANCIAL 2003-B OWNER TRUST,  which  is
           attached as Exhibit 20 hereto.


Item 9.01  Financial Statements and Exhibits.


         (c)      See attached Exhibit 20.


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                                   SIGNATURE


Pursuant  to the  requirements  of the  Securities  Exchange  Act of  1934,  the
Registrant  has duly  caused  this  report  to be  signed  on its  behalf by the
undersigned thereunto duly authorized.


                      NAVISTAR FINANCIAL 2003-B OWNER TRUST
             (Exact name of Registrant as specified in its charter)



Date:  MayJune 2624, 2005                                             By:/s/ PAUL E. MARTIN
-----------------------                          --------------------------
                                                 Paul E. Martin
                                                 Vice President & Controller


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                                  EXHIBIT INDEX

Exhibit No.    Description

   20          Navistar Financial 2003-B Owner Trust
               Monthly Servicer Certificate #1920, dated MayJune 1615, 2005


================================================================================


                                  Exhibit 20

                                       Navistar Financial 2003 - B Owner Trust
                                                   For the Month of AprilMay 2005
                                           Distribution Date of MayJune 1615, 2005
                          Servicer Certificate  #1920

Original Pool Amount                                                                                  $354,999,927.08
Subsequent Receivables (transferred 11/21/03)                                $194,998,039.46
Subsequent Receivables (transferred xx/xx/xx)                                                    $0.00
Subsequent Receivables (transferred xx/xx/xx)                                                    $0.00
Subsequent Receivables (transferred xx/xx/xx)                                                    $0.00
Beginning Pool Balance                                                                              $322312,513586,849578.6748
Beginning Pool Factor                                                                                            0.58639105683413

Principal and Interest Collections:
    Principal Collected (Incl. Servicer Advance Repay)                  $9,855500,347161.4346
    Interest Collected                                                                                  $1,744695,878391.6891
    Mandatory Prepayments                                                                                            $0.00
Additional Deposits:

    Repurchase Amounts                                                                                                  $0.00

    Liquidation Proceeds / Recoveries                                                         $15876,499039.4374
Total Additional Deposits                                                                                 $15876,499039.4374

Repos / Chargeoffs                                                                                                $7163,923030.7678
Aggregate Number of Notes Charged Off                                    62                                      65

Total Available Funds                                                                                  $11,758198,725949.5450

Ending Pool Balance                                                                                    $312303,586096,578029.4885
Ending Pool Factor                                                                                                  0.56834135510857

Servicing Fee                                                                                                        $268260,761488.5482
    memo: Servicer will allocate $1,500.00 of Servicing Fee
          as Administration Fee
Repayment of Servicer Advances                                                                             $072,643.0061
                                                                                   
Reserve Account:
                                                                                        ====================================
                                                                                        Beginning Balance  (see Memo Item)                         $17,766,876.79           Memo Item - Reserve Account
Reserve    Target Account:                                                                   Percentage                                                    5.50%          Opening balance      $17,738192,261.7382
                                                                                       Target Balance                                             $16,670,281.64           + Trans Base                  $0.00
    BeginningSpecified Balance  (seeYield MemoSupplement Item)                       Amount                                   $18,596,3780.72        00           + Trans Low/0%                $0.00
    TargetSpecified Percentage                                                 5Yield Supplement Amount                                   $0.50%        00           + Invest. Income         $3842,730125.7003
    TargetSpecified Reserve Account Balance                                                                     $1716,192670,261281.82        64           + Excess Serv.          $819532,386489.2994
    SpecifiedMinimum Yield Supplement Amount                                 Balance                                            $010,999,959.00        33           + Transfer (to)               $0.00
                                                                                                                                                                                                                  -----------------
    Specified(Release) Yield/ Supplement Amount                                 Deposit                                        ($01,096,595.00          Collections15)            Collection Acct
    SpecifiedEnding Reserve Account Balance                                                                     $1716,192670,261281.82          64             Beginning Balance  $1817,596766,378876.7279
                                                                                                                                                                           =====================================
    Minimum Balance                                          $10,999,959.33
    (Release) / Deposit                                      ($1,404,116.90)
    Ending Balance                                           $17,192,261.82

------------------------------------------------------------------------------
Current Weighted Average APR:                                                                                  6.438421%
------------------------------------------------------------------------------
------------------------------------------------------------------------------
Current Weighted Average Remaining Term (months):                     36                       35.8093
------------------------------------------------------------------------------

Delinquencies                                                                                                           Dollars          Notes
    Installments:     1 - 30 days                                                                 1,399267,793309.34  14     1,300190
                                     31 - 60 days                              147                                       220,902924.01    16344       179
                                     60+  days                                  74                                           67,100558.65     4203        27

           Total:                                                                                            1,621555,796791.00  61     1,305198
        Balances:   60+  days                                 986                                          737,921973.62     4266        27


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Navistar Financial 2003 - B Owner Trust
For the Month of AprilMay 2005
                                                                                                                                  NOTES
                                                                                   TOTAL                 CLASS A - 1         CLASS A - 2     CLASS A - 3     CLASS A - 4       CLASS B NOTES
                                    Original Pool Amount                  $550,000,000.00   $93,400,000.00 $163,500,000.00 $160,000,000.00 $111,100,000.00 $22,000,000.00
Original Pool Amount

Distributions:
   Distribution Percentages  (1)                                                              0.00%          96.00%           0.00%           0.00%                   4.00%

   Coupon                                                                                                    1.140630%       1.690000%       3.153750290000%       3.250000%           3.790000%


Beginning Pool Balance                              $322312,513586,849578.6748
Ending Pool Balance                                    $312303,586096,578029.4885

Collected Principal                                        $9,855427,347517.4385
Collected Interest                                          $1,744695,878391.6891
Charge - Offs                                                          $7163,923030.7678
Liquidation Proceeds / Recoveries                 $15876,499039.4374
Swap Payments to/(from)Trust                           ($9389,627013.7862)
Servicing & Administration Fee                      $268260,761488.5482
Investment Earnings from Pre-Funding Acct.          $0.00
Cash Transfer from Negative Carry Acct.                $0.00
Cash Transfer from Pre-Funding Acct.                      $0.00
Cash Transfer from Reserve Account                          $0.00
Total Collections Avail for Debt Svc    $1110,583849,591447.7806

Beginning Balance                                        $322312,513586,849578.67          48           $0.00  $3425,777247,295115.6935 $160,000,000.00 $111,100,000.00 $16,636239,553463.9813

Interest Due (2)                                                  $836826,934408.30          49           $0.00      $4835,978556.0235     $434438,516666.67     $300,895.83     $5251,543289.7864
Interest Paid                                                        $836826,934408.30          49           $0.00      $4835,978556.0235     $434438,516666.67     $300,895.83     $5251,543289.7864
Principal Due                                                    $9,927490,271548.19          63           $0.00   $9,530110,180926.3468           $0.00           $0.00    $397379,090621.8595
Mandatory Prepayments Class A-1 only **                $0.00                     $0.00
Principal Paid                                                  $9,927490,271548.19          63           $0.00   $9,530110,180926.3468           $0.00           $0.00    $397379,090621.8595

Ending Balance                                              $312303,586096,578029.48          85           $0.00  $2516,247136,115188.3567 $160,000,000.00 $111,100,000.00 $1615,239859,463841.1318

Note/Certificate Pool Factor
           (Ending Balance/Original Pool AmtAmount)                                         0.0000          0.15440987          1.0000          1.0000         0.73827209
Total Distributions                                      $10,764316,205957.49          12           $0.00   $9,579146,158483.3603     $434438,516666.67     $300,895.83    $449430,634911.6359



Interest Shortfall                                                          $0.00                     $0.00           $0.00           $0.00           $0.00          $0.00
Principal Shortfall                                                        $0.00                     $0.00           $0.00           $0.00           $0.00          $0.00
   Total Shortfall                                                          $0.00                     $0.00           $0.00           $0.00           $0.00          $0.00
Excess Servicing
   (see Memo Item - Reserve Account)          $819532,386489.2994

   Beginning Reserve Acct Balance             $1817,596766,378876.7279
   (Release) / Draw                                         ($1,404096,116595.9015)
   Ending Reserve Acct Balance                   $1716,192670,261281.8264

(1)   Principal distributions will be paid in the following priority:  First to Class A-1 until paid in full, second 96.00% applied
    sequentially to Class A notes and 4.00% to Class B notes until all Class A Notes are repaid in full, then 100% to Class B Notes.
(2)   Class A-1 Interest based on Actual Number of Days.  Interest  for first settlement based off 17 days, from 10/31/03 to 11/17/03
    for Class A-1 and A-3.  Class A-2, and  A-4 and Class B Interest calculated  on 15 days.
(3)   LIBOR was reset on 56/1213/05 at 3.0900022000%.  The Interest Rate on the Class A-3a  Floating Rate Notes for the 67/15/05 Distribution
    Date is 3.2900042000%.

(* x represents previously paid interest to other classes.)
(* y represents previously paid interest and principal on other classes.)
==============================================================
Memo Item - Advances:
   Servicer Advances - Current Reporting Period     ($23572,800643.8361)
   Total Outstanding Servicer Advances                   $2,514442,649005.3675
==============================================================


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Navistar Financial 2003 - B Owner Trust
For the Month of AprilMay 2005

Trigger Events:  A)  Loss Trigger
                                B)  Delinquency Trigger
                                C)  Noteholders Percent Trigger

                                                                                 5                                  4               3               2                               1               0
                                      Nov-04                                                    Dec-04                     Jan-05                   Feb-05                     Mar-05                   Apr-05           May-05
Remaining Gross Balance                       $419,416,120.85    $405,017,554.94    $391,128,247.17 $379,342,007.93 $366,612,722.55 $352,520,384.26 $341,310,836.19

A)   Loss Trigger:
Principal of Contracts Charged Off         $174,817.15        $184,109.66            $305,409.54     $285,365.36     $181,899.51      $71,923.76
Recoveries                                    $563,889030.63        78

Recoveries                             $147,991.98              $68,426.04     $122,296.62     $170,514.77     $158,499.43      $76,039.74

Total Charged Off (Months 5, 4, 3)         $664774,336884.3556
Total Recoveries (Months 3, 2, 1)           $361451,237310.4382
                                                                      ----------------
Net Loss / (Recoveries) for 3 Mos           $303323,098573.92 74(a)

Total Balance (Months 5, 4, 3)     $1,215175,561487,922810.9604(b)

Loss Ratio Annualized [(a/b) * (12)]                 0.29923303%

Trigger:  Is Ratio > 1.5%                                           No
                                                                                        Feb-05           Mar-05          Apr-05           May-05

B)   Delinquency Trigger:
     Balance delinquency 60+ days                                                                                                         $1,275,918.83      $598,305.04           $986,921.62      $737,973.66
     As % of Remaining Gross Balance                                                                                                           0.3363516320%         0.1632027996%                 0.2799621622%
     Three Month Average                                                                                                                                   0.3847927686%         0.2768625984%                 0.2598421979%

Trigger:  Is Average > 2.0%                                       No

C)   Noteholders Percent Trigger:                    3.12590310%
     Ending Reserve Account Balance
     not less than 1% of Initial Aggregate
     Receivables Balance

Trigger:  Is Minimum < 1.0%                                       No


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Filing Compare · NAVISTAR FINANCIAL RETAIL REC CORP 2003 B OWNER TRUST
