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                                                                  EXHIBIT 4.3

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                        TRANSAMERICAN ENERGY CORPORATION

                                       AND

                           TRANSTEXAS GAS CORPORATION


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                       SECOND AMENDMENT TO LOAN AGREEMENT

                          Dated as of December 15, 1998

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                       SECOND AMENDMENT TO LOAN AGREEMENT

         This Second Amendment to Loan Agreement (this "Second Amendment") is
made as of December 15, 1998, by and between TransAmerican Energy Corporation, a
Delaware corporation ("TEC"), and TransTexas Gas Corporation, a Delaware
corporation ("TransTexas").

         WHEREAS, TEC and Firstar Bank of Minnesota, N.A., as Trustee, have
entered into an Indenture dated as of June 13, 1997, as amended (the
"Indenture"), pursuant to which TEC issued $475,000,000 aggregate principal
amount of its 11 1/2% Senior Secured Notes due 2002 and $1,130,000,000 aggregate
principal amount of its 13% Senior Secured Discount Notes due 2002
(collectively, the "Notes"); and

         WHEREAS, TEC and TransTexas have entered into a Loan Agreement dated as
of June 13, 1997, as amended by a First Amendment to Loan Agreement dated as of
December 30, 1997 (as so amended, the "TransTexas Intercompany Loan Agreement"),
pursuant to which TEC agreed to loan to TransTexas an aggregate of $450,000,000
out of the proceeds of the issuance of the Notes; and

         WHEREAS, TEC and TransTexas have agreed to certain amendments to the
TransTexas Intercompany Loan Agreement as hereinafter set forth (the "Proposed
Amendments"); and

         WHEREAS, pursuant to Section 9.2 of the Indenture, the holders of not
less than 66-2/3% in aggregate Value (as defined in the Indenture) of the Notes
have consented to the Proposed Amendments to the TransTexas Intercompany Loan
Agreement;

         NOW, THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the parties to this Second
Amendment hereby agree as follows:


                                    ARTICLE I
            AMENDMENTS TO THE TRANSTEXAS INTERCOMPANY LOAN AGREEMENT

         Section 1.01. Amendments to Section 1.1. The following definitions in
Section 1.1 of the TransTexas Intercompany Loan Agreement are hereby amended as
follows:

         (a)      The definition of "Equipment" is hereby amended to read as 
follows:

                           "Equipment" shall mean and includes all of any
                  Person's now owned or hereafter acquired Vehicles, drilling
                  rigs, workover rigs, fracture stimulation equipment, well site
                  compressors, rolling stock and related equipment and other
                  assets accounted for as equipment by such Person in its
                  financial statements, all proceeds thereof, and all documents
                  of title, books, records, ledger cards, files, correspondence
                  and computer files, tapes, disks and related data processing
                  software that any time evidence or contain information
                  relating to the foregoing; provided, however that "Equipment"
                  shall not include any assets constituting part of a natural
                  gas pipeline or the compression or dehydration equipment used
                  in the operation of any such pipeline; provided further,
                  however, notwithstanding the foregoing, "Equipment" shall
                  include (x) production related facilities, (y) assets
                  comprising amine plants and (z) equipment and related assets
                  designed to dehydrate, compress, treat, separate, stabilize,
                  store or otherwise process hydrocarbons,


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                  including, without limitation, the facilities at Winnie, Texas
                  (including the real property associated with such facilities
                  at Winnie, Texas).

         (b) The definition of "Permitted Hedging Transactions" is hereby
amended to read as follows:

                           "Permitted Hedging Transactions" shall mean
                  non-speculative transactions in futures, forwards, swaps or
                  option contracts (including both physical and financial
                  settlement transactions) engaged in by the TransTexas Entities
                  as part of their normal business operations as a
                  risk-management strategy or hedge against adverse changes in
                  market conditions in the prices of natural gas, condensate,
                  feedstock or refined products; provided, that such
                  transactions do not in the case of the Borrower, on a monthly
                  basis, relate to more than 90% of the TransTexas Entities'
                  average net hydrocarbon production per month from the
                  Continuing Operations for the most recent 3-month period
                  measured at the time of such incurrence; provided, further,
                  that, at the time of such transaction (i) the counter party to
                  any such transaction is an Eligible Institution or a Person
                  that has an Investment Grade Rating or has an issue of debt
                  securities or preferred stock outstanding with an Investment
                  Grade Rating or (ii) such counter party's obligation pursuant
                  to such transaction is unconditionally guaranteed in full by,
                  or secured by a letter of credit issued by, an Eligible
                  Institution or a Person that has an Investment Grade Rating or
                  that has an issue of debt securities or preferred stock
                  outstanding with an Investment Grade Rating.

         (c) The definition of "Permitted Investment" is hereby amended to read
as follows:

                           "Permitted Investment" shall mean, when used with
                  reference to the Borrower or its Subsidiaries, (i) trade
                  credit extended to persons in the ordinary course of business;
                  (ii) purchases of Cash Equivalents; (iii) Investments by the
                  Borrower or its wholly owned Subsidiaries in wholly owned
                  Subsidiaries of the Borrower (other than TTXD) that are
                  engaged in Related TransTexas Businesses; (iv) Swap
                  Obligations; (v) the receipt of capital stock in lieu of cash
                  in connection with the settlement of litigation; (vi) advances
                  to officers and employees in connection with the performance
                  of their duties in the ordinary course of business in an
                  amount not to exceed $3 million in the aggregate outstanding
                  at any time; (vii) margin deposits in connection with
                  Permitted Hedging Transactions; (viii) an Investment in one or
                  more Unrestricted Subsidiaries of the Borrower in an aggregate
                  amount, net return of income on such investment, not in excess
                  of $25 million less the amount of any Unrestricted
                  Non-Recourse Debt outstanding of Borrower or any of its
                  Subsidiaries; (ix) Investments and expenditures made in the
                  ordinary course of business by the Borrower or its
                  Subsidiaries, and of a nature that is or shall have become
                  customary in, the oil and gas business as a means of actively
                  exploiting, exploring for, acquiring, developing, processing,
                  gathering, marketing or transporting oil and gas or providing
                  services with respect to such activities through agreements,
                  transactions, interests or arrangements which permit a person
                  to share risks or costs, comply with regulatory requirements
                  regarding local ownership or satisfy other objectives
                  customarily achieved through the conduct of the oil and gas
                  business jointly with third parties, including, without
                  limitation, (a) ownership interests in oil and gas properties
                  or gathering systems and (b) Investments and expenditures in
                  the form of or pursuant to operating agreements, processing
                  agreements, farm-in agreements, farm-out agreements,
                  development agreements, area of mutual interest agreements,
                  unitization agreements, pooling arrangements, joint

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                  bidding agreements, service contracts, joint venture
                  agreements, partnership agreements (whether general or
                  limited), subscription agreements, stock purchase agreements
                  and other similar agreements with third parties (including
                  Unrestricted Subsidiaries); provided, that in the case of any
                  joint venture primarily engaged in processing, gathering,
                  marketing or transporting oil or gas (i) all Debt of such
                  joint venture (other than a joint venture that is an
                  Unrestricted Subsidiary) that would not otherwise constitute
                  Debt of one of the TransTexas Entities shall be deemed Debt of
                  the Borrower in proportion to its direct or indirect ownership
                  interest in such joint venture (other than through an
                  Unrestricted Subsidiary) and (ii) such joint venture shall be
                  reasonably calculated to enhance the value of the reserves of
                  the TransTexas Entities or marketability of production from
                  such reserves; (x) a guaranty by any Subsidiary of the
                  Borrower permitted under the Indenture; (xi) deposits
                  permitted by the definition of Permitted Liens or any
                  extension, renewal or replacement of any of them; (xii) the
                  TTXD Equity Investment (in addition to any contribution by the
                  Borrower pursuant to clause (xiii) below, (xiii) a capital
                  contribution by the Borrower to TTXD or to a joint venture, a
                  partnership, a limited liability company or a similar entity
                  of the Borrower's drilling and energy services business and
                  pipeline services business and related assets, (xiv) an
                  acquisition by the Borrower of tank storage facilities (or the
                  company that owns such facilities) in the vicinity of the TARC
                  Refinery; (xv) guarantees by the Borrower of Debt of TTXD to
                  the extent such Debt relates to assets contributed to TTXD
                  pursuant to clause (xiii) hereof; (xvi) other Investments not
                  in excess of $5 million at any time outstanding, (xvii) loans
                  made (x) to officers, directors and employees of the Borrower
                  or any of its Subsidiaries approved by the applicable Board of
                  Directors (or by an authorized officer), the proceeds of which
                  are used solely to purchase stock or to exercise stock options
                  received pursuant to an employee stock option plan or other
                  incentive plan, in a principal amount not to exceed the
                  purchase price of such stock or the exercise price of such
                  stock options, as applicable, and (y) to refinance loans,
                  together with accrued interest thereon made pursuant to this
                  clause, in each case not in excess of $3 million in the
                  aggregate outstanding at any one time, (xviii) a capital
                  contribution by the Borrower of any or all of its assets to a
                  joint venture, a partnership, a limited liability company or a
                  similar entity, (xix) any deposit or escrow of funds in
                  connection with adjustments to the Lobo Sale purchase price or
                  (xx) the acquisition by the Borrower of TEC Notes as a result
                  of a capital contribution to the Borrower by a Person other
                  than the Lender or any of its Subsidiaries.

         (d) The definition of "Permitted Liens" is hereby amended to read as
follows:

                           "Permitted Liens" shall mean (a) Liens imposed by
                  governmental authorities for taxes, assessments, or other
                  charges not yet due or which are being contested in good faith
                  and by appropriate proceedings, if adequate reserves with
                  respect thereto are maintained on the books of any of the
                  TransTexas Entities in accordance with GAAP; (b) statutory
                  Liens of landlords, carriers, warehousemen, mechanics,
                  materialmen, repairmen, mineral interest owners, or other like
                  Liens arising by operation of law in the ordinary course of
                  business; provided, that (i) the underlying obligations are
                  not overdue for a period of more than 60 days, or (ii) such
                  Liens are being contested in good faith and by appropriate
                  proceedings and adequate reserves with respect thereto are
                  maintained on the books of any of the TransTexas Entities in
                  accordance with GAAP; (c) (i) pledges of assets or deposits of
                  cash or Cash Equivalents to secure the performance of bids,
                  trade contracts (other than

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                  borrowed money), leases, statutory obligations, surety bonds,
                  performance bonds and other obligations of a like nature
                  incurred in the ordinary course of business (or to secure
                  reimbursement obligations or letters of credit in support of
                  such bonds) in an aggregate amount not in excess of 5% of the
                  SEC PV10 indicated on TransTexas' most recent Reserve Report
                  at the time such pledges or deposits are made or (ii) pledges
                  of assets, the fair market value of which is not in excess of
                  $40 million in the aggregate pledged at any one time, or
                  deposits of cash or Cash Equivalents, in each case, to secure
                  appeal or supersedeas bonds (or to secure reimbursement
                  obligations or letters of credit in support of such bonds);
                  (d) Liens encumbering customary initial deposits and margin
                  deposits securing Swap Obligations or Permitted Hedging
                  Transactions; (e) pledges of assets including, without
                  limitation, the mortgage of a production payment by a Hedging
                  Subsidiary, to secure margin obligations, settlement
                  obligations, reimbursement obligations or letters of credit in
                  connection with Permitted Hedging Transactions; provided that,
                  at the time such pledge is made (or, if such pledge secures
                  future Permitted Hedging Transactions, at the time any such
                  Permitted Hedging Transaction is entered into), the maximum
                  aggregate exposure under such Permitted Hedging Transactions
                  does not exceed the greater of (i) $25 million or (ii) 10% of
                  the SEC PV10 indicated on TransTexas' then most recent Reserve
                  Report; (f) easements, rights-of-way, zoning, similar
                  restrictions and other similar encumbrances or title defects
                  incurred in the ordinary course of business which, in the
                  aggregate, are not material in amount, and which do not in any
                  case materially detract from the value of the property subject
                  thereto (as such property is used by any of the TransTexas
                  Entities) or materially interfere with the ordinary conduct of
                  the business of any of the TransTexas Entities; (g) Liens
                  arising by operation of law in connection with judgments, only
                  to the extent, for an amount and for a period not resulting in
                  an Event of Default with respect thereto; (h) Liens securing
                  Debt or other obligations not in excess of $3 million and
                  Liens existing on the Closing Date; (i) pledges or deposits
                  made in the ordinary course of business in connection with
                  worker's compensation, unemployment insurance, and other types
                  of social security legislation, property insurance and
                  liability insurance; (j) Liens granted on Equipment, Inventory
                  or Receivables; (k) Liens granted in connection with the
                  Presale of Gas, provided that all of the proceeds from such
                  Presale of Gas shall be applied to the repurchase of the Note;
                  (l) Liens created on acreage drilled or to be drilled pursuant
                  to Drilling Programs, on Hydrocarbons produced therefrom and
                  on the proceeds of such Hydrocarbons to secure TransTexas'
                  obligations thereunder, provided that (i) the number of wells
                  included in such program commenced in any fiscal year does not
                  exceed 30 per fiscal year (plus the number of wells included
                  in programs commenced in prior years but not yet completed),
                  (ii) such obligations are limited to a percentage of
                  production from such wells, (iii) such Liens survive only
                  until the Person to whom such Lien was granted has received
                  production with a value equal to the reimbursable costs,
                  expenses and fees related to property and services provided or
                  paid for by such Person plus an agreed-upon interest
                  component, and (iv) such Liens secure obligations that are
                  nonrecourse to each of the Company or its Subsidiaries; (m)
                  Liens on the assets of any entity existing at the time such
                  assets are acquired by any of the TransTexas Entities, whether
                  by merger, consolidation, purchase of assets or otherwise so
                  long as such Liens (A) are not created, incurred or assumed in
                  contemplation of such assets being acquired by any of the
                  TransTexas Entities and (B) do not extend to any other assets
                  of any of the TransTexas Entities; (n) any extension, renewal,
                  or replacement of Liens created pursuant to any of clauses (a)
                  through (g), (i), (k) through (m) or (q) through (t) of this
                  definition, or (r) through (v) ;provided that

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                  such Liens would have otherwise been permitted under such
                  clauses, and further provided that the Liens permitted by this
                  clause (n) do not secure any additional Debt or encumber any
                  additional property; (o) Liens securing (i) Royalty Payment
                  Obligations and (ii) Permitted Production Payment Obligations;
                  (p) Liens on the assets of one of the TransTexas Entities in
                  favor of another TransTexas Entity; (q) Liens that secure
                  Unrestricted NonRecourse Debt; provided however, that at the
                  time of incurrence the aggregate fair market value of the
                  assets securing such Lien (exclusive of the stock of the
                  applicable Unrestricted Subsidiary) shall not exceed the
                  amount of allowed Unrestricted Non-Recourse Debt of the
                  Borrower; (r) Liens on the proceeds of any property subject to
                  a Permitted Lien or on deposit accounts containing any such
                  proceeds; (s) Liens on the proceeds of any property that is
                  not Collateral, on the proceeds of any Debt incurred in
                  accordance with the provisions hereof, or on deposit accounts
                  containing any such proceeds; (t) Liens (including extensions
                  and renewals thereof) on real or personal property, acquired
                  after the Closing Date ("New TransTexas Property"); provided,
                  however, that (A) such Lien is created solely for the purpose
                  of securing Debt Incurred to finance the cost (including the
                  cost of improvements or construction) of New TransTexas
                  Property subject thereto and such Lien is created at the time
                  of, or within six months after the later of the acquisition,
                  the completion of construction, or the commencement of full
                  operation of such New TransTexas Property, (B) the principal
                  amount of the Debt secured by such Lien does not exceed 100%
                  of such cost plus reasonable financing fees and other
                  associated reasonable out-of-pocket expenses and (C) any such
                  Lien shall not extend to or cover any property or assets other
                  than such item of New TransTexas property and any improvements
                  on such New TransTexas Property; (u) Liens of the trustee
                  under the indenture and related collateral documents governing
                  the terms of the TransTexas Senior Notes and (v) Liens in
                  favor of the Lender or its assignee under the TransTexas
                  Security Documents.

         (e) The definition of "Phase I Completion Date" is hereby amended to
read as follows:

                           "Phase I Completion Date" shall mean the date on
                  which the Construction Supervisor issues a written notice (the
                  "Phase I Completion Notice") to TARC certifying that the Phase
                  I Performance Test has been completed.

         (f) The definition of "Phase I Performance Test" is hereby added to the
TransTexas Intercompany Loan Agreement to read in its entirety as follows:

                           "Phase I Performance Test" means for a period of at
                  least 72 uninterrupted hours, TARC Operating's refinery has
                  sustained (i) an average feedstock throughput level of at
                  least 150,000 barrels per day, and (ii) no net production of
                  vacuum tower bottoms when using as input a combined feedstock
                  slate with an average API Gravity of 22 degrees or less.

         (g) The definition of "Phase II Completion Date" is hereby amended to
read as follows:

                           "Phase II Completion Date" means the date on which
                  the Construction Supervisor issues a written notice (the
                  "Phase II Completion Notice") to the Borrower certifying that
                  for a period of at least 72 uninterrupted hours, TARC
                  Operating's refinery has sustained (i) an average feedstock
                  throughput level of at least 180,000 barrels per day and (ii)
                  average

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                  production yields (measured as the liquid volume percent of
                  feedstock throughput) of refined products with a specific
                  gravity of gasoline or lighter of at least 40% and of middle
                  distillates or lighter of at least 60%, when using a combined
                  Crude Unit feedstock slate with an average API Gravity of 22
                  degrees or less.

         (h) The definition of "Related TransTexas Business" is hereby amended
to read as follows:

                           "Related TransTexas Business" shall mean (i) the
                  exploration for, acquisition of, development of, production,
                  transportation, gathering, and processing (in connection with
                  natural gas and natural gas liquids only) of, crude oil,
                  natural gas, condensate, and natural gas liquids; provided
                  that the Related TransTexas Business shall not include any
                  refining or distilling of Hydrocarbons other than processing
                  and fractionating natural gas and natural gas liquids, (ii)
                  the drilling and energy services business and pipeline
                  services business, (iii) owning and operating a Hedging
                  Subsidiary or (iv) owning and operating facilities in or near
                  Winnie, Texas, designed for separation, dehydration,
                  treatment, stabilization, processing and storage of
                  hydrocarbons and related operations.

         Section 1.02. Section 2.4 of the TransTexas Intercompany Loan
Agreement. Section 2.4 of the TransTexas Intercompany Loan Agreement is hereby
amended to add a new subsection (b) following subsection (a) to read as follows:

                           (b) Notwithstanding anything to the contrary herein,
                  the Borrower may at any time repay the principal of the Loan
                  by surrender to the Lender for cancellation of 11 1/2% Senior
                  Secured Notes due 2000 of the Lender ("Senior Notes") and at
                  any time after June 15, 1999 repay the principal of the Loan
                  by surrender to the Lender for cancellation of 13% Senior
                  Secured Discount Notes due 2002 ("Senior Discount Notes"), but
                  only to the extent the Borrower has received Senior Notes or
                  Senior Discount Notes or a cash amount equal to the cost to
                  the Borrower of such Senior Notes or Senior Discount Notes as
                  a capital contribution from a person other than the Lender or
                  any of its Subsidiaries. Upon each such surrender of Senior
                  Notes or Senior Discount Notes to the Lender, the principal
                  amount of the Loan shall be reduced by 100.0% of the principal
                  amount of the Senior Notes surrendered and 100.0% of the
                  principal amount of the Senior Discount Notes surrendered.

         Section 1.03. Section 3.2 of the TransTexas Intercompany Loan
Agreement. Section 3.2 of the TransTexas Intercompany Loan Agreement is hereby
amended to read as follows:

                           Section 3.2 Permitted Prepayments. The Borrower may
                  at any time make a prepayment of all or a portion of the
                  principal amount of the Note then outstanding (a "Permitted
                  Prepayment") at a prepayment price equal to the portion of the
                  outstanding principal amount of the Note to be prepaid
                  together with accrued and unpaid interest, if any, to and
                  including the date of such Permitted Prepayment.

         Section 1.04. Section 9.15 of the TransTexas Intercompany Loan
Agreement. A Section 9.15 is hereby added to the TransTexas Intercompany Loan
Agreement to read as follows:

                           Section 9.15 Agreement. The term "Agreement," as used
                  in the TransTexas Intercompany Loan Agreement, and the terms
                  "TransTexas Intercompany Loan Agreement"

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                  and "Loan Agreement," as used in the other Loan Documents,
                  each shall mean and refer to the TransTexas Intercompany Loan
                  Agreement, as amended, modified, supplemented, restated,
                  renewed, and/or extended from time to time; . . .


                                   ARTICLE II
                                  MISCELLANEOUS

         Section 2.01. Ratification and Confirmation. As amended and modified by
this Second Amendment, the terms and provisions of the TransTexas Intercompany
Loan Agreement are hereby ratified and confirmed and shall continue in full
force and effect.

         Section 2.02. Reference to TransTexas Intercompany Loan Agreement. The
TransTexas Intercompany Loan Agreement and any and all other agreements,
documents or instruments now or hereafter executed and delivered pursuant to the
terms of the TransTexas Intercompany Loan Agreement, are hereby amended so that
any reference therein to the TransTexas Intercompany Loan Agreement shall mean a
reference to the TransTexas Intercompany Loan Agreement as amended hereby.

         Section 2.03. Counterparts. This Second Amendment may be executed in
one or more counterparts, each of which when executed shall be deemed to be an
original, but all of which when taken together shall constitute one and the same
instrument.

         Section 2.04. Headings. The headings, captions and arrangements used in
this Second Amendment are for convenience only and shall not affect the
interpretation of this Second Amendment.

         Section 2.05. Governing Law. THIS SECOND AMENDMENT SHALL BE CONSTRUED
IN ACCORDANCE WITH AND GOVERNED BY THE LAWS OF THE STATE OF NEW YORK, WITHOUT
REGARD TO PRINCIPLES OF CONFLICTS OF LAWS.

         Section 2.06. Effectiveness of Amendments. This Second Amendment is
effective as of the date first above written. However, the provisions of the
TransTexas Intercompany Loan Agreement amended or eliminated as provided in this
Second Amendment (the "Amended Provisions") shall remain operative in the form
in which they exist in the TransTexas Intercompany Loan Agreement until the
Transaction Closing Date, whereupon the Amended Provisions will be amended or
eliminated as provided herein, effective immediately prior to the Transaction
Closing Date.



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         IN WITNESS WHEREOF, the parties hereto have caused this Second
Amendment to be executed as of the date of first written above.


                                     TRANSTEXAS GAS CORPORATION



                                     By:
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                                     Name:
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                                     Title:
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                                     TRANSAMERICAN ENERGY CORPORATION



                                     By:
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                                     Name:
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                                     Title:
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