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) December 17, 2014

Ally Auto Receivables Trust 2014-3

(Issuing Entity with respect to Securities)

Ally Auto Assets LLC

(Depositor with respect to Securities)

Ally Bank

(Sponsor with respect to Securities)

Registrant’s Telephone Number, including area code: (313) 656-5500

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Item 1.01 and 8.01. Entry into a Material Definitive Agreement and Other Events

Ally Auto Assets LLC (“Ally Auto”) has registered an issuance of $24,098,660,000 in principal amount of asset backed notes on Form S-3 (Registration File No. 333-186227) under the Securities Act of 1933, as amended (the “Act”), filed on January 25, 2013, as amended by Pre-Effective Amendment No. 1 on April 12, 2013 (as amended, the “Registration Statement”).

Pursuant to the Registration Statement, Ally Auto Receivables Trust 2014-3 (the “Issuing Entity”) issued $215,000,000 aggregate principal balance of Class A-1 0.27000% Asset Backed Notes (the “Class A-1 Notes”), $310,000,000 aggregate principal balance of Class A-2 0.81% Asset Backed Notes (the “Class A-2 Notes”), $334,000,000 aggregate principal balance of Class A-3 1.28% Asset Backed Notes (the “Class A-3 Notes”), $98,830,000 aggregate principal balance of Class A-4 1.72% Asset Backed Notes (the “Class A-4 Notes” and together with the Class A-1 Notes, the Class A-2 Notes and the Class A-3 Notes, the “Class A Notes”), $21,300,000 aggregate principal balance of Class B 2.04% Asset Backed Notes (the “Class B Notes”), $17,550,000 aggregate principal balance of Class C 2.14% Asset Backed Notes (the “Class C Notes”), and $16,430,000 aggregate principal balance of Class D 2.88% Asset Backed Notes (the “Class D Notes” and together with the Class A Notes, the Class B Notes and the Class C Notes, the “Notes”) on December 17, 2014 (the “Closing Date”). The Notes have an aggregate principal balance of $1,013,110,000. Only the Notes were offered publicly for sale. On the Closing Date, Ally Auto sold the Certificates of the Issuing Entity in one or more separate transactions exempt from the registration requirements of the Act.

This Current Report on Form 8-K is being filed to satisfy an undertaking to file copies of certain agreements executed in connection with the issuance of the Notes, the forms of which were filed as Exhibits to the Registration Statement.

The Notes were issued pursuant to an Indenture attached hereto as Exhibit 4.1, dated as of the Closing Date, between the Issuing Entity and Deutsche Bank Trust Company Americas, as Indenture Trustee.

The Notes evidence indebtedness of the Issuing Entity, the assets of which consist primarily of motor vehicle retail instalment sale contracts (the “Receivables”) secured by new and used automobiles and light duty trucks financed thereby.

As of the Closing Date, the Receivables had the characteristics described in the Prospectus Supplement, dated as of December 10, 2014, filed with the Commission pursuant to Rule 424(b)(5) of the Act on December 12, 2014.

SIGNATURES

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 hereunto duly authorized.

Dated: December 17, 2014

EXHIBIT INDEX