Exhibit
31.1







I,
Susan B. Sheffield, certify that:



| | 1. | I
                                         have reviewed this report on Form 10-K and all reports on Form 10-D required to be filed
                                         in respect of the period covered by this report on Form 10-K of AmeriCredit Automobile
                                         Receivables Trust 2018-3 (the “Exchange Act periodic reports”);
| | -- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



| | 2. | Based
on my knowledge, the Exchange Act periodic reports, taken as a whole, do not contain any untrue statement of a material fact or
omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements
were made, not misleading with respect to the period covered by this report;
| | -- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



| | 3. | Based
on my knowledge, all of the distribution, servicing and other information required to be provided under Form 10-D for the period
covered by this report is included in the Exchange Act periodic reports;
| | -- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



| | 4. | Based
on my knowledge and the servicer compliance statement required in this report under Item 1123 of Regulation AB, and except as
disclosed in the Exchange Act periodic reports, the servicer has fulfilled its obligations under the servicing agreements in all
material respects; and
| | -- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



| | 5. | All
of the reports on assessment of compliance with servicing criteria for asset-backed securities and their related attestation reports
on assessment of compliance with servicing criteria for asset-backed securities required to be included in this report in accordance
with Item 1122 of Regulation AB and Exchange Act Rules 13a-18 and 15d-18 have been included as an exhibit to this report, except
as otherwise disclosed in this report. Any material instances of noncompliance described in such reports have been disclosed in
this report on Form 10-K.
| | -- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



In giving the certifications above, I have reasonably relied on information provided to me by the following unaffiliated parties:  Citibank, N.A.



|By:    | /s/ Susan
    B. Sheffield                           | 
|------ | ---------------------------------------------------- | 
|Name:  | Susan B. Sheffield                                   | 
|Title: | Executive Vice President and Chief Financial Officer | 
|Date:  | March 8, 2019                                        |