UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G (Amendment No. Six)* Rush Enterprises, Inc. (Name of Issuer) Common Stock (Title of Class of Securities) 781846209 (Cusip Number) December 31, 2017 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which this Schedule is filed: [x] Rule 13d-1(b) [ ] Rule 13d-1(c) [ ] Rule 13d-1(d) *The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page. The information required in the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes). 1. NAME OF REPORTING PERSON S.S. OR I.R.S. INDENTIFICATION NO. OF ABOVE PERSON: NewSouth Capital Management, Inc. Tax ID #: 62-1237220 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*(a)[ ] (b)[ ] 3. SEC USE ONLY 4. CITIZENSHIP OR PLACE OF ORGANIZATION Tennessee NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH: 5. SOLE VOTING POWER 614,884 6. SHARED VOTING POWER None 7. SOLE DISPOSITIVE POWER 755,694 8. SHARED DISPOSITIVE POWER None 9. AGGREGATE AMOUNT BENEFICALLY OWNED BY EACH REPORTING PERSON 755,694 10. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES N/A 11. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 2.4% 12. TYPE OF REPORTING PERSON* I/A Item 1. (a) Name of Issuer: Rush Enterprises, Inc. Item 1. (b) Address of Issuer's Principal Executive Offices: 555 I.H. 35 South, Suite 500 New Braunfels, Texas 78130 Item 2. (a) Name of Person Filing: NewSouth Capital Management, Inc. Item 2. (b) Address of Principal Business Office: 999 S. Shady Grove Rd. Suite 501 Memphis, TN 38120 Item 2. (c) Citizenship: USA Item 2. (d) Title of Class of Securities: Common Stock Item 2. (e) CUSIP Number: 781846209 Item 3. (e) /x/ Investment Adviser registered under Section 203 of the Investment Advisers Act of 1940 Item 4. Ownership: (a) Amount Beneficially Owned: 755,694 (b) Percent of Class: 2.4% (c) Number of Shares as to which such person has: (i) Sole Power to vote or to direct the vote: 614,884 (ii) Shared Power to vote or to direct the vote: None (iii) Sole Power to dispose or to direct the disposition of: 755,694 (iv) Shared Power to dispose or to direct the disposition of: None Of the 755,694 shares being reported, 28,556 or .09% of the outstanding shares of Common Stock of Rush Enterprises, Inc. are managed by NewSouth Capital Management, Inc. through a Thomas Weisel Partners Investment Management Consulting Program whereby accounts are placed with NewSouth for management. Although discretionary responsibility for the accounts is with NewSouth, Thomas Weisel Partners retains responsibility for SEC filings should their cumulative holdings trigger the need for 13G reporting. Item 5. Ownership of Five Percent or Less of a Class: If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check the following [X]. Item 6. Ownership of More than Five Percent on Behalf of Another Person: N/A Item 7. Identification and Classification of the subsidiary which Acquired the Security Being Reported on By the Parent Holding Company: N/A Item 8. Identification and Classification of Members of the Group: N/A Item 9. Notice of Dissolution of Group: N/A Item 10. Certification: By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired in the ordinary course of business and were not acquired for the purpose of and do not have the effect of changing or influencing the control of the issuer of such securities and were not acquired in connection with or as a participant in any transaction having such purposes or effect. After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct. Date: 02/13/2017 as of 12/31/2017 Signature:__________________________ Name: David M. Newman Title: Vice President