22527 Loose Fasteners May Cause Rear Axle Instability – 2023 IC Bus RE, IC Bus EV, & 2023-2024 IC Bus CE School Buses

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OMB Control No.: 2127-0004 Part 573 Safety Recall Report 22V-909 The information contained in this report was submitted pursuant to 49 CFR §573 Manufacturer Name : Navistar, Inc. Submission Date : DEC 08, 2022 NHTSA Recall No. : 22V-909 Manufacturer Recall No. : 22527 Manufacturer Information : Manufacturer Name : Navistar, Inc. Address : 2701 Navistar Drive Lisle IL 60532 Company phone : 331-332-1590 Population : Number of potentially involved : 6,948 Estimated percentage with defect : 100 % Vehicle Information : Vehicle 1 : 2023-2024 IC CE school bus Vehicle Type : BUSES, MEDIUM & HEAVY VEHICLES Body Style : OTHER Power Train : DIESEL Descriptive Information : • The suspect population is identified by models equipped with feature code 14TBH, 14TBS, or 14TBT (Suspension, rear, air single; International IROS). • The inclusive dates of manufacture were determined by warranty data / first failure build date and when the issue was contained in manufacturing. • The vehicles in the suspect population were built at a certain assembly plant where all vehicles not subject to this recall were built at other manufacturing plants. There are 6,551 CE school buses in the suspect population Production Dates : FEB 01, 2022 – NOV 15, 2022 VIN Range 1 : Begin : NR End : NR Not sequential Vehicle 2 : 2023-2023 IC RE school bus Vehicle Type : BUSES, MEDIUM & HEAVY VEHICLES Body Style : OTHER Power Train : DIESEL Descriptive Information : • The suspect population is identified by models equipped with feature code 14TBH, 14TBS, or 14TBT (Suspension, rear, air single; International IROS). • The inclusive dates of manufacture were determined by warranty data / first failure build date and when the issue was contained in manufacturing. • The vehicles in the suspect population were built at a certain assembly plant where all vehicles not subject to this recall were built at other manufacturing plants. There are 275 RE school buses in the suspect population Production Dates : FEB 01, 2022 – NOV 15, 2022 VIN Range 1 : Begin : NR End : NR Not sequential Part 573 Safety Recall Report 22V-909 Page 2 The information contained in this report was submitted pursuant to 49 CFR §573 Vehicle 3 : 2023-2023 IC EV school bus Vehicle Type : BUSES, MEDIUM & HEAVY VEHICLES Body Style : OTHER Power Train : HYBRID ELECTRIC Descriptive Information : • The suspect population is identified by models equipped with feature code 14TBH, 14TBS, or 14TBT (Suspension, rear, air single; International IROS). • The inclusive dates of manufacture were determined by warranty data / first failure build date and when the issue was contained in manufacturing. • The vehicles in the suspect population were built at a certain assembly plant where all vehicles not subject to this recall were built at other manufacturing plants. There are 122 EV school buses in the suspect population Production Dates : FEB 08, 2022 – NOV 15, 2022 VIN Range 1 : Begin : NR End : NR Not sequential Description of Defect : Description of the Defect : The fasteners of the transverse torque arm to the rear axle housing may not have been tightened to their specified value at time of assembly. Over time, they may become loose or separate, resulting in the rear axle to shift from side to side. FMVSS 1 : NR FMVSS 2 : NR Description of the Safety Risk : In a bus application, a rear axle that shifts from side to side can cause reduced handling performance and may result in evacuation concerns when students must be transferred to another bus near the roadway. Description of the Cause : The tool used to assemble the transverse torque rod to the rear axle housing incorrectly gave the operator an indication it had reached the correct torque value when it did not. Identification of Any Warning that can Occur : A general “loose” feeling when driving, possible metallic clunking noise in the rear of the vehicle or during pre/post trip inspections the rear axle does not appear centered to the bus body. Involved Components : Component Name 1 : NR Component Description : NR Component Part Number : NR Part 573 Safety Recall Report 22V-909 Page 3 The information contained in this report was submitted pursuant to 49 CFR §573 Supplier Identification : Component Manufacturer Name : N/A – Manufacturing issue Address : NR NR Country : NR Chronology : • 08/05/2022 – Navistar Field Service reviews field reports of four units with loose transverse torque rod axle side bolts on units in service less than three months. • 08/10/2022 – Navistar’s Tulsa bus plant inspected 10 units built in March and all were found in specification. Additionally, the tool and process for the transverse torque rod to axle joint were inspected with no issues found. • 08/11/2022 through 09/22/2022 – Nine more units were found with loose of missing axle side fasteners. • 09/22/2022 – Navistar Field Service received communication of three more units with axle side fasteners missing on units in service for less than three months. • 09/26/2022 – IC Bus dealer inspected 90 units at one location. All but 5 had their fasteners retightened to their specified value. • 10/31/2022 – IC Bus dealer reinspected 10 of the fleet; four units found with bolts loose a second time. These fasteners were replaced and sent to Navistar engineering for analysis. • 11/11/2022 – Navistar completes the part analysis for material hardness and found no deficiencies. • 11/16/2022 – Navistar contains the issue in manufacturing by instituting a secondary torque top-off operation. • 11/22/2022 – Navistar finalizes the suspect population. • 12/01/2022 – Navistar declares a Safety Recall. Description of Remedy : Description of Remedy Program : • The remedy will involve replacing the transverse torque rod to axle fasteners and tightening them to their specified value. • Navistar’s plan for reimbursement of pre-notification remedies, on file with NHTSA and dated 05/06/2022, applies and reimbursement instructions will be included in the customer notification. How Remedy Component Differs from Recalled Component : The remedy will involve replacing the fasteners and tightening them to their assembly value where the recalled fasteners were not tightened to their specified value. Identify How/When Recall Condition was Corrected in Production : 11/16/2022 – Navistar manufacturing adds the use of a top-off torque wrench and witness mark to the joint’s fasteners. Part 573 Safety Recall Report 22V-909 Page 4 The information contained in this report was submitted pursuant to 49 CFR §573 Recall Schedule : Description of Recall Schedule : It is estimated that the Customer and Dealer notification letters will be mailed by 02/06/2023. Planned Dealer Notification Date : FEB 06, 2023 – FEB 06, 2023 Planned Owner Notification Date : FEB 06, 2023 – FEB 06, 2023 * NR – Not Reported

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OMB Control No.: 2127-0004 Part 573 Safety Recall Report 22V-909 The information contained in this report was submitted pursuant to 49 CFR §573 Manufacturer Name : Navistar, Inc. Submission Date : DEC 13, 2022 NHTSA Recall No. : 22V-909 Manufacturer Recall No. : 22527 Manufacturer Information : Manufacturer Name : Navistar, Inc. Address : 2701 Navistar Drive Lisle IL 60532 Company phone : 331-332-1590 Population : Number of potentially involved : 6,948 Estimated percentage with defect : 100 % Vehicle Information : Vehicle 1 : 2023-2024 IC CE school bus Vehicle Type : BUSES, MEDIUM & HEAVY VEHICLES Body Style : OTHER Power Train : DIESEL Descriptive Information : • The suspect population is identified by models equipped with feature code 14TBH, 14TBS, or 14TBT (Suspension, rear, air single; International IROS). • The inclusive dates of manufacture were determined by warranty data / first failure build date and when the issue was contained in manufacturing. • The vehicles in the suspect population were built at a certain assembly plant where all vehicles not subject to this recall were built at other manufacturing plants. There are 6,551 CE school buses in the suspect population Production Dates : FEB 01, 2022 – NOV 15, 2022 VIN Range 1 : Begin : NR End : NR Not sequential Vehicle 2 : 2023-2023 IC RE school bus Vehicle Type : BUSES, MEDIUM & HEAVY VEHICLES Body Style : OTHER Power Train : DIESEL Descriptive Information : • The suspect population is identified by models equipped with feature code 14TBH, 14TBS, or 14TBT (Suspension, rear, air single; International IROS). • The inclusive dates of manufacture were determined by warranty data / first failure build date and when the issue was contained in manufacturing. • The vehicles in the suspect population were built at a certain assembly plant where all vehicles not subject to this recall were built at other manufacturing plants. There are 275 RE school buses in the suspect population Production Dates : FEB 01, 2022 – NOV 15, 2022 VIN Range 1 : Begin : NR End : NR Not sequential Part 573 Safety Recall Report 22V-909 Page 2 The information contained in this report was submitted pursuant to 49 CFR §573 Vehicle 3 : 2023-2023 IC EV school bus Vehicle Type : BUSES, MEDIUM & HEAVY VEHICLES Body Style : OTHER Power Train : HYBRID ELECTRIC Descriptive Information : • The suspect population is identified by models equipped with feature code 14TBH, 14TBS, or 14TBT (Suspension, rear, air single; International IROS). • The inclusive dates of manufacture were determined by warranty data / first failure build date and when the issue was contained in manufacturing. • The vehicles in the suspect population were built at a certain assembly plant where all vehicles not subject to this recall were built at other manufacturing plants. There are 122 EV school buses in the suspect population Production Dates : FEB 08, 2022 – NOV 15, 2022 VIN Range 1 : Begin : NR End : NR Not sequential Description of Defect : Description of the Defect : The fasteners of the transverse torque arm to the rear axle housing may not have been tightened to their specified value at time of assembly. Over time, they may become loose or separate, resulting in the rear axle to shift from side to side. FMVSS 1 : NR FMVSS 2 : NR Description of the Safety Risk : In a bus application, a rear axle that shifts from side to side can cause reduced handling performance and may result in an increased risk of injury if students must be transferred to another bus near the roadway. Description of the Cause : The tool used to assemble the transverse torque rod to the rear axle housing incorrectly gave the operator an indication it had reached the correct torque value when it did not. Identification of Any Warning that can Occur : A general “loose” feeling when driving, possible metallic clunking noise in the rear of the vehicle or during pre/post trip inspections the rear axle does not appear centered to the bus body. Involved Components : Component Name 1 : Bolt and Hex Nut Component Description : Bolt and Hex Nut Component Part Number : 31077R1 (BOLT) / 30756R1 (Nut Hex) Part 573 Safety Recall Report 22V-909 Page 3 The information contained in this report was submitted pursuant to 49 CFR §573 Supplier Identification : Component Manufacturer Name : N/A – Manufacturing issue Address : NR NR Country : NR Chronology : • 08/05/2022 – Navistar Field Service reviews field reports of four units with loose transverse torque rod axle side bolts on units in service less than three months. • 08/10/2022 – Navistar’s Tulsa bus plant inspected 10 units built in March and all were found in specification. Additionally, the tool and process for the transverse torque rod to axle joint were inspected with no issues found. • 08/11/2022 through 09/22/2022 – Nine more units were found with loose of missing axle side fasteners. • 09/22/2022 – Navistar Field Service received communication of three more units with axle side fasteners missing on units in service for less than three months. • 09/26/2022 – IC Bus dealer inspected 90 units at one location. All but 5 had their fasteners retightened to their specified value. • 10/31/2022 – IC Bus dealer reinspected 10 of the fleet; four units found with bolts loose a second time. These fasteners were replaced and sent to Navistar engineering for analysis. • 11/11/2022 – Navistar completes the part analysis for material hardness and found no deficiencies. • 11/16/2022 – Navistar contains the issue in manufacturing by instituting a secondary torque top-off operation. • 11/22/2022 – Navistar finalizes the suspect population. • 12/01/2022 – Navistar declares a Safety Recall. Description of Remedy : Description of Remedy Program : • The remedy will involve replacing the transverse torque rod to axle fasteners and tightening them to their specified value. • Navistar’s plan for reimbursement of pre-notification remedies, on file with NHTSA and dated 05/06/2022, applies and reimbursement instructions will be included in the customer notification. How Remedy Component Differs from Recalled Component : The remedy will involve replacing the fasteners and tightening them to their assembly value where the recalled fasteners were not tightened to their specified value. Identify How/When Recall Condition was Corrected in Production : 11/16/2022 – Navistar manufacturing adds the use of a top-off torque wrench and witness mark to the joint’s fasteners. Part 573 Safety Recall Report 22V-909 Page 4 The information contained in this report was submitted pursuant to 49 CFR §573 Recall Schedule : Description of Recall Schedule : It is estimated that the Customer and Dealer notification letters will be mailed by 02/06/2023. Planned Dealer Notification Date : FEB 06, 2023 – FEB 06, 2023 Planned Owner Notification Date : FEB 06, 2023 – FEB 06, 2023 * NR – Not Reported

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