EXHIBIT 5.1

                   [MAYER, BROWN, ROWE & MAW LLP LETTERHEAD]


May 24, 2004

Tenneco Automotive Inc.
500 North Field Drive
Lake Forest, Illinois  60045

     Re:   Common Stock, $.01 par value per share, of Tenneco Automotive Inc.
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Ladies and Gentlemen:

         We refer to the Registration Statement on Form S-3 of Tenneco
Automotive Inc., a Delaware corporation (the "Company"), filed with the
Securities and Exchange Commission ("SEC") under the Securities Act of 1933, as
amended (the "Securities Act"), with registration number 333-114520 (the
"Registration Statement"). The Registration Statement relates to the
registration of common stock, par value $0.01 per share (the "Common Stock"), of
the Company with a maximum aggregate offering price of $175 million, together
with the five preferred stock purchase rights associated with each share of
Common Stock so registered (the "Rights"). The terms of the Rights are set forth
in the Rights Agreement, dated as of September 9, 1998, between the Company and
First Union National Bank, as rights agent and successor to First Chicago Trust
Company of New York, as amended (the "Rights Agreement").

         In rendering this letter, we have examined and relied upon a copy of
the Registration Statement and the exhibits filed therewith. We have also
examined originals or copies, certified or otherwise identified to our
satisfaction, of such writings, corporate records, certificates of public
officials and Company officers and other agreements and instruments, and have
examined such questions of law and satisfied ourselves as to such matters of
fact, as we have deemed necessary or appropriate as a basis for the opinions set
forth herein. We have assumed the genuineness of all signatures, the
authenticity of all writings, certificates, instruments and records submitted to
us as originals, the conformity to originals of all such writings, certificates,
instruments and records submitted to us as certified, conformed or photostatic
copies, the authenticity of the originals of such copies, and the truthfulness
of all statements of fact set forth therein. We have also assumed that the
Rights Agreement, as in effect on the date hereof, remains in effect on the date
of any issuance of Common Stock pursuant to the Registration Statement.

         Based on the foregoing, and subject to the qualifications and
limitations hereinafter set forth, we are of the opinion that:

         1.  The Company is a duly incorporated and validly existing corporation
under the laws of the State of Delaware.
         2.  Assuming (a) the Registration Statement is effective under the
Securities Act, (b) the Board of Directors of the Company (or a duly authorized
committee thereof) has established the final amount of shares of Common Stock to
be issued (the "Shares") and the consideration to be paid therefor and (c) such
consideration is lawful and has a value not less than the par value of such
Shares,





upon receipt by the Company of such consideration, the Shares will be validly
issued, fully paid and non-assessable.

         3.   When issued in accordance with the Rights Agreement, the Rights
associated with the Shares will be validly issued.

         The opinion set forth in paragraph 3 hereof is limited to the valid
issuance of the Rights under the General Corporation Law of the State of
Delaware. In connection therewith, we do not express any opinion herein with
respect to any other aspect of the Rights, including, without limitation, the
effect of any equitable principles or fiduciary considerations relating to the
adoption or issuance of the Rights, the enforceability of any particular
provisions of the Rights Agreement or the provisions of the Rights Agreement
which discriminate or create unequal voting power among stockholders.

         This letter is limited to the General Corporation Law of the State of
Delaware. We assume no obligation to update or supplement this opinion to
reflect any facts or circumstances that may hereafter come to our attention with
respect to the opinions expressed above, including, without limitation, any
changes in applicable law that may hereafter occur.

         We hereby consent to the filing of this letter as Exhibit 5.1 to the
Registration Statement and to all references to our Firm included in the
Registration Statement. In giving such consent, we do not thereby admit that we
are within the category of persons for whom consent is required by Section 7 of
the Securities Act or the related rules promulgated by the SEC thereunder.

                          Very truly yours,

                          /s/ Mayer, Brown, Rowe & Maw LLP

                          Mayer, Brown, Rowe & Maw LLP