THIRD AMENDMENT AGREEMENT To Pledge and Security Agreement and Irrevocable Proxy

Exhibit 10.18

EXECUTION COPY

THIRD AMENDMENT AGREEMENT

To Pledge and Security Agreement and Irrevocable Proxy

Dated as of June 1, 2009

by and among

RFC ASSET HOLDINGS II, LLC,

PASSIVE ASSET TRANSACTIONS, LLC

AND CERTAIN

AFFILIATES THEREOF FROM

TIME TO TIME PARTY HERETO,

as Grantors,

and

GMAC LLC,

as Lender Agent

This THIRD AMENDMENT AGREEMENT (this “ Agreement ”) dated as of June 1, 2009 (the “ Amendment Effective Date ”), is by and among RFC Asset Holdings II, LLC, a Delaware limited liability company (“ RAHI ”), and Passive Asset Transactions, LLC, a Delaware limited liability company (“ PATI ”; and together with RAHI, each a “ Borrower ” and collectively, the “ Borrowers ”); Residential Capital, LLC, a Delaware limited liability company (“ ResCap ”), Residential Funding Company, LLC, a Delaware limited liability company (“ RFC ”), and GMAC Mortgage, LLC, a Delaware limited liability company (“ GMAC Mortgage ”; and together with ResCap and RFC, each herein a “ Guarantor ” and collectively, the “ Guarantors ”), and the other parties hereto as Grantors (each, together with each Borrower and each Guarantor, a “ Grantor ” and collectively, the “ Grantors ”); and GMAC LLC, a Delaware limited liability company, as Lender Agent for the Lender Parties.

Reference is hereby made to the Pledge and Security Agreement and Irrevocable Proxy dated as of November 20, 2008 among the Grantors and the Lender Agent (as amended and modified through the date hereof, the “ Security Agreement ”).

RECITALS

1. Each of the parties hereto is a party to the Security Agreement.

2. The parties hereto desire to make certain amendments to the Security Agreement.

3. Each of the parties hereto, by its signature hereto, hereby acknowledges, consents and agrees to the changes set forth herein.

4. In consideration of the promises and mutual agreements herein contained and for good and valuable consideration, the receipt and sufficiency of which is hereby acknowledged, the parties hereto agree as follows:

ARTICLE I

DEFINED TERMS

SECTION 1.1 Capitalized terms used herein and not otherwise defined shall have the meaning set forth in the Security Agreement.

ARTICLE II

AMENDMENTS TO THE SECURITY AGREEMENT

SECTION 2.1 Amendments to Section 1 . Section 1 to the Security Agreement is hereby amended by amending and restating the following definitions:

“ Obligations means obligations, indebtedness, fees, expenses (including, without limitation, attorneys’ fees and expenses ) and liabilities of any ResCap Counterparty or Grantor under any Specified Document, now existing or hereafter arising under or in connection with the Specified Documents, whether monetary or otherwise, matured or unmatured, direct, indirect, related, unrelated, fixed, contingent, liquidated, unliquidated, joint, several, or joint and several, and any interest accruing thereon (including any interest that accrues after the commencement of any proceeding by or against any ResCap Counterparty or any

other Person under any bankruptcy, insolvency, liquidation, moratorium, receivership, reorganization or other debtor relief law) and all attorneys’ fees and other expenses incurred in the collection or enforcement thereof; including without limitation (a) the obligations, indebtedness and liabilities of the ResCap Counterparties under the Master Netting Agreement or otherwise pursuant to the terms of the other Derivative Documents, (b) all other “Obligations” as defined in the Loan Agreement, (c) all other “Secured Obligations” as defined in the MSR Loan Agreement, and (d) all other “Obligations” as defined in the Credit Agreement.

Permitted Liens means (a) Liens arising under this Agreement or the other Security Documents, (b) with respect to all “Collateral” as defined in the November Security Agreement, any Liens permitted under the Loan Agreement, (c) with respect to all Derivative Collateral, any Liens permitted under the Derivative Documents, (d) with respect to all “Collateral” as defined in the MSR Loan Agreement, any Liens permitted under the MSR Loan Agreement and (e) with respect to all “Collateral” as defined in the Credit Agreement, any Liens permitted under the Credit Agreement.

Secured Parties means (i) GMAC IM, (ii) GMAC LLC, as lender under the MSR Loan Agreement, (iii) each “Indemnified Party” under and as defined in the MSR Loan Agreement, (iv) the Lender Agent, for the benefit of the “Lender Parties” under and as defined in the Loan Agreement, (v) the Credit Agent, for the benefit of the “Lender Parties” under and as defined in the Credit Agreement and (vi) any other Person to whom any Obligation is owed.”

Specified Documents means (i) each of the Derivative Documents, (ii) each of the November Documents, (iii) each of the MSR Documents, (iv) each of the Credit Documents and (v) this Agreement.”

SECTION 2.2 Amendments to Section 1 . Section 1 to the Security Agreement is hereby amended by inserting the following definitions in the proper alphabetical order:

“ Credit Agent means GMAC LLC, in its capacity as agent for the “Lender Parties” under and as defined in the Credit Agreement.

Credit Agreement means that certain Credit Agreement, dated as of June 1, 2009, as amended, supplemented, restated or otherwise modified from time to time, among RAHI and PATI, as borrowers, ResCap, RFC, and GMAC Mortgage, as guarantors, and GMAC LLC, as agent and initial lender, and certain other financial institutions and Persons from time to time party thereto as lenders, pursuant to which the lenders thereunder have agreed to make loans to RAHI and PATI.

Credit Documents means the Credit Agreement, the notes issued thereunder by RAHI and PATI as borrowers thereunder, the Fourth Security Agreement (as defined in the Credit Agreement), and all notices, certificates, financing statements, agreements and other documents to be executed and delivered by RAHI, PATI, ResCap, RFC or GMAC Mortgage pursuant to the foregoing or otherwise in connection with the Credit Agreement or the extension of financing contemplated thereunder.”

ARTICLE III

CONDITIONS TO EFFECTIVENESS

SECTION 3.1 Amendment Effective Date . This Agreement and the provisions contained herein shall become effective as of the Amendment Effective Date.

SECTION 3.2 Opinions . On or before June 1, 2009, the Obligors shall deliver or cause to be delivered opinions of counsel to the Borrowers, the Guarantors and Obligors with respect to the transactions contemplated hereby, which opinions shall be in form and substance satisfactory to the Lender Agent.

SECTION 3.3 Other . On or before June 1, 2009, the Obligors shall deliver or cause to be delivered such other documents, including but not limited to the Obligors’ board resolutions approving this Agreement, as the Lender Agent may reasonably request, which documents will be in form and s