<PAGE>

                                                                 EXHIBIT 10.4(f)

               FIFTH AMENDMENT TO REVOLVING CREDIT LOAN AGREEMENT

         THIS FIFTH AMENDMENT TO REVOLVING CREDIT LOAN AGREEMENT (the
"Amendment") is entered into as of the 5th day of July, 2003, by and between
SUNTRUST BANK, a Georgia state banking corporation (the "Lender"), and CENTRAL
FREIGHT LINES, INC., a Texas corporation (the "Borrower").

                                    RECITALS:

         A.       Borrower and Lender entered into that certain Revolving Credit
Loan Agreement dated April 30, 2002, as most recently amended by that certain
Fourth Amendment to Revolving Credit Loan Agreement dated May ____, 2003 (the
"Loan Agreement").

         B.       The Borrower and the Lender desire to amend the Loan Agreement
as set forth herein.

         C.       Terms not defined herein shall have the meanings ascribed to
such terms in the Loan Agreement.

         NOW, THEREFORE, in consideration of the premises and mutual covenants
and obligations herein, the parties hereto agree that the Loan Agreement is
hereby amended and modified as follows:

         Section 1.        The minimum Tangible Net Worth requirement set forth
in Section 6.1 of the Loan Agreement for the fiscal quarter ending as of July 5,
2003 is hereby changed to a flat amount equal to $26,500,000 with no additions
thereto.

         Section 2.        As of July 6, 2003 and on a going forward basis
thereafter, Section 6.1 of the Loan Agreement concerning "Minimum Tangible Net
Worth" is amended to substitute $26,500,000 for $25,500,000 and to commence the
addition of 50% of Net Income and 100% of all equity proceeds, both measured on
a cumulative basis as of the last day of each Fiscal Quarter of Borrower for
each Fiscal Year of Borrower, to such new base net worth; provided, that if Net
Income is negative for any period the amount added for such period shall be zero
and such negative Net Income shall not reduce the amount of Net Income added
from any previous period. In addition, as of the closing of any initial public
offering of equity securities by the Borrower, Minimum Tangible Net Worth shall
be increased by the net proceeds to the Borrower, Parent, and its consolidated
group less a dividend of all previously taxed income, less a separation payment
to Central Refrigerated of up to $8.5 million (and notwithstanding anything to
the contrary, such payment is hereby approved and any default under the Loan
Agreement is waived), and less the booking of a non-cash deferred tax liability
upon conversion to a C corporation.

         Section 3.        Except as provided herein, the Loan Agreement shall
remain unamended in full force and effect.

         Section 4.        This modification shall be governed by and construed
in accordance with the laws of the State of Tennessee.

<PAGE>

         IN WITNESS WHEREOF, the undersigned by and through their duly
authorized officers hereby execute this Amendment as of the day and date first
set forth above.

BORROWER:                                    LENDER:

CENTRAL FREIGHT LINES, INC.                  SUNTRUST BANK

By: /s/ Jeff Hale                            By: /s/ William H. Crawford
    --------------------------------             -------------------------------

Title: CFO                                   Title: Director