23E079 – Transmission May Separate from Driveshaft – Allison Transmission B3400 xFE & B400R

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OMB Control No.: 2127-0004 Part 573 Safety Recall Report 23E-079 The information contained in this report was submitted pursuant to 49 CFR §573 Manufacturer Name : Allison Transmission, Inc. Submission Date : OCT 11, 2023 NHTSA Recall No. : 23E-079 Manufacturer Recall No. : 2023FA04 Manufacturer Information : Manufacturer Name : Allison Transmission, Inc. Address : One Allison Way Indianapolis IN 46222 Company phone : 317-242-5000 Population : Number of potentially involved : 8,498 Estimated percentage with defect : 25 % Equipment Information : Brand / Trade 1 : Allison Transmission Model : B3400xFE_R Part No. : B3400xFE_R Size : NR Function : Output Yoke Bol Descriptive Information : The output yoke bolt connects the driveline yoke to the transmission output shaft. Allison Transmission, Inc. (ATI) supplied approximately 1,281 transmissions equipped with the subject bolt to OEM customers for use primarily in municipal transit bus duty cycle. The recall scope was determined based upon a review of production shipping records. Production Dates : JAN 01, 2019 – OCT 02, 2023 Part 573 Safety Recall Report 23E-079 Page 2 The information contained in this report was submitted pursuant to 49 CFR §573 Brand / Trade 2 : Allison Transmission Model : B400R Part No. : B400R Size : NR Function : Output Yoke Bol Descriptive Information : The output yoke bolt connects the driveline yoke to the transmission output shaft. Allison Transmission, Inc. (ATI) supplied approximately 7,217 transmissions equipped with the subject bolt to OEM customers for use primarily in municipal transit bus duty cycle. The recall scope was determined based upon a review of production shipping records. Production Dates : JAN 01, 2019 – OCT 02, 2023 Description of Defect : Description of the Defect : Under certain conditions, the output yoke bolt may loosen and potentially result in separation of the driveline from the transmission output shaft. FMVSS 1 : NR FMVSS 2 : NR Description of the Safety Risk : If the driveline separates from the transmission output shaft while driving, the vehicle may experience an unexpected loss of propulsion, which may increase the risk of a crash. Additionally, an immobilized transit bus presents a potential risk of injury to passengers if they are offloaded in an unsuitable environment. Description of the Cause : ATI has not yet determined the cause of the loosening of the output yoke bolt. Transit bus duty cycles have a very high start/stop shift density. This generates significantly more torsional activity on this bolted joint than other applications. Testing by ATI and its customer is ongoing. Identification of Any Warning that can Occur : The failure could occur without warning. Involved Components : Part 573 Safety Recall Report 23E-079 Page 3 The information contained in this report was submitted pursuant to 49 CFR §573 Component Name : Output Yoke Bolt Component Description : Bolt connecting plate 29535213 and yoke 29540327 to output shaft 29540991 Component Part Number : PN29535219 Supplier Identification : Component Manufacturer Name : Allison Transmission Address : NR NR Country : NR Chronology : – June 26-27, 2023: ATI learned of potential loose output yoke bolts and separated drivelines in Canada involving Nova Bus vehicles and that Nova Bus conducted a field survey that identified loose output bolts. – July 10, 2023: ATI began noise, vibration, harshness (NVH) testing on select Nova Buses jointly with Nova Bus. – July 12, 2023: Nova Bus submitted a defect information report to NHTSA related to the issue. See Recall No. 23V482. – July 19, 2023: ATI Opened a formal investigation. – Jul. – Sep. 2023: ATI investigated potential causes of the Nova Bus reports and collected data related to torque specifications for the output yoke bolt. ATI learned of complaints of driveline cases for transit buses manufactured by another vehicle manufacture. ATI investigated the additional claims and conducted a field survey of transit buses to inspect transmissions for loose output yoke bolts. – Sep. 25, 2023: After confirming reports of loose bolts in buses produced by additional vehicle manufacturers, ATI escalated the issue to its Field Performance Evaluation Review Committee (FPERC). – Sep. 26, 2023: ATI’s FPERC made its recommendation to ATI’s Executive Field Action Decision Committee (EFADC). – Oct. 4, 2023: Based on the information developed during the investigation, ATI – through the EFADC – agreed that the condition constituted a safety-related defect. ATI is not aware of any accidents or injuries related to this condition. Part 573 Safety Recall Report 23E-079 Page 4 The information contained in this report was submitted pursuant to 49 CFR §573 Description of Remedy : Description of Remedy Program : ATI is working with OEMs to inspect the output yoke bolts and, if necessary, tighten loose output yoke bolts. Pursuant to 49 CFR 577.11(e), ATI requests that it be exempt from providing notification or a reimbursement plan. Pre-notification product failures would have been addressed under the terms of the ATI’s or vehicle manufacturer’s warranty or goodwill. How Remedy Component Differs from Recalled Component : ATI increased the torque specification for the output yoke bolt for all B400R and B3400xFE_R transmissions. The clamp load for the output yoke bolt was increased by approximately 150%, nominal torque is being increased from the previous specification of 77.5 Newton-meters (N?m) to130 N?m. Identify How/When Recall Condition was Corrected in Production : On October 3, 2023, ATI implemented a specification change that increased the torque on the output yoke bolt from 77.5 N?m to 130 N?m. Recall Schedule : Description of Recall Schedule : The timing of owner notifications will be determined in consultation with the affected OEMs. In cases where ATI will contact owners, ATI is prepared to commence owner notification on the dates noted. Planned Dealer Notification Date : OCT 16, 2023 – OCT 16, 2023 Planned Owner Notification Date : OCT 27, 2023 – OCT 27, 2023 Purchaser Information : The following manufacturers purchased this defective/noncompliant equipment for possible use or installation in new motor vehicles or new items of motor vehicle equipment: Name : Gillig Address : 451 Discovery Dr Livermore CA 94551 Country : US Company Phone : 5102645075 Name : New Flyer Address : 4141 SW 30th Ave Fort Lauderdale FL 33312 Country : US Company Phone : 2564537181 Part 573 Safety Recall Report 23E-079 Page 5 The information contained in this report was submitted pursuant to 49 CFR §573 Name : Nova Bus Address : 260 Banker Road Plattsburg NY 12901 Country : US Company Phone : 4388431428 Name : ENC – Eldorado National Address : NR 00 Country : NR Company Phone : NR * NR – Not Reported

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*** IMPORTANT SAFETY RECALL *** NHTSA Recall No. 23E079 Sent via email and Courier October 20, 2023 OEM Customer List recipient name List email addresses sent to Dear [OEM]: We are writing to advise you that Allison Transmission Inc. (ATI) has initiated a new voluntary safety recall to address an issue with the output yoke bolt on certain B3400xFE_R and B400R model transmissions manufactured between January 1, 2019, and October 2, 2023, used in transit buses. The affected Transmissions that are being added to this campaign are within the serial number range XXXXXXXXX through XXXXXXXXX. Under certain conditions, the output yoke bolt may loosen and potentially result in separation of the driveline from the transmission output shaft. If the bolt loosens enough, the driveline could separate from the transmission output shaft. If the driveline separates from the transmission output shaft while driving, the vehicle may experience unexpected loss of propulsion, which may increase the risk of a crash. Additionally, an immobilized transit bus that loses propulsion in an environment that is unsuitable for offloading passengers may present a risk of injury to passengers. Please refer to Field Action 2023FA04. A 573 Defect Information Report was submitted to NHTSA on October 11, 2023. (Copy attached.) Attached is a list of serial numbers shipped to you within the affected range. ATI’s authorized service network will be utilized to inspect and, if necessary, ensure the clamp load on the output yoke bolt in each affected drive unit at no charge to the customer. ATI expects the repair time to range from 1.0 to 1.5 hours, excluding vehicle and shop logistics. For drive units installed in vehicles that have left your control, we encourage you to make a safety defect determination in accordance with 49 U.S.C. 30118 et seq. and, as appropriate, to submit a Defect Notification to NHTSA in accordance with 49 CFR Part 573. At your option, ATI will conduct the recall, including notifying owners pursuant to 49 CFR Part 577 and performing the remedy. If you desire to conduct the owner notification, please advise your ATI OEM Account Manager. ATI would like to review the letter prior to customer distribution. Attached is a copy of ATI’s owner notification letter, which is being reviewed by NHTSA. If you would like ATI to handle owner notification, we request the following information for each owner be provided no later than November 17, 2023:  Customer Name  Mailing Address  Vehicle Identification Number  Transmission Serial Number  Contact Information o First Name o Last Name o Position o Email o Phone Questions regarding this campaign may be directed to: Larry Hansen Director, Field Performance Evaluations Larry.hansen@allisontransmission.com (317) 242-3712 Please confirm receipt of this communication. Sincerely, Account Manager Enclosures: 1. ATI Part 573 Defect Notification 2. Owner Notification Letter 3. List of Affected Transmission

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