Recall 19V686 affects 618 2017-2020 Thomas Built Buses Saf-T-Liner C2 school buses for loose torque-converter fasteners. Free repair at a franchised Thomas Built Buses dealer.
Thomas Built Buses is recalling 618 2017-2020 Saf-T-Liner C2 school buses equipped with Detroit DD5 engines and Allison transmissions because flex-plate and torque converter fasteners were not tightened enough. Loose bolts can disable the bus and force an evacuation in uncontrolled traffic, increasing injury risk; Thomas Built Buses dealers will complete the free repair.
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What's wrong?
The flex plate and torque converter sit between the Detroit DD5 engine and Allison transmission in these 2017-2020 Thomas Built Buses Saf-T-Liner C2 school buses. The flex plate helps transfer engine rotation into the transmission, while the torque converter lets the bus move smoothly from a stop. The fasteners hold those parts tightly together inside the flywheel housing.
On affected buses, those fasteners were not tightened to the required torque at the plant. Without enough clamp load, the bolts loosen, break, or dislodge inside the flywheel housing. A loose or broken bolt can damage the flex plate, lodge in the starter, and leave the school bus disabled.
The warning signs are mechanical and electrical. The check engine light can come on, the flex plate can be damaged, or a loose bolt can get into the starter area before the bus shuts down or cannot restart.
Who's affected?
Covers the 2017, 2018, 2019, and 2020 model years, with the automatic transmission torque converter listed as the shared component.
| 2017 Thomas Built Buses Saf-T-Liner C2 | automatic transmission |
|---|---|
| 2019 Thomas Built Buses Saf-T-Liner C2 | automatic transmission |
| 2018 Thomas Built Buses Saf-T-Liner C2 | automatic transmission |
| 2020 Thomas Built Buses Saf-T-Liner C2 | automatic transmission |
| Units affected | 618 |
| Field incidents | NHTSA has logged 5 field incidents to date. |
A matching year and model does not guarantee inclusion. Check your VIN to confirm whether this recall applies to your specific bus.
What's the safety risk?
Loose bolts can disable the school bus and force an evacuation in uncontrolled traffic, increasing injury risk. If the check engine light comes on, or the starter acts abnormally, remove the bus from service and call the dealer. Repair is free at any franchised Thomas Built Buses dealer.
What should I do?
- Check your VIN to confirm your 2017-2020 Thomas Built Buses Saf-T-Liner C2 is included in this recall.
- Contact a franchised Thomas Built Buses dealer to schedule the free inspection and tightening of the Flex-Plate/Torque Converter fasteners that can loosen and disable the bus.
- Bring the recall notice if Thomas Built Buses mailed one. If not, reference recall number 19V686 and DTNA recall FL-828 when you call.
- Plan service before regular routes so a loose fastener does not leave the school bus disabled in traffic.
- Call Thomas Built Buses customer service at 1-800-547-0712 with questions about the repair or scheduling.
What happens at the repair
At the dealer, a Thomas Built Buses technician inspects the Flex-Plate/Torque Converter fasteners and tightens them if they are loose. The inspection and any needed tightening are free under the recall. If you already paid for a related repair before the owner notice, Thomas Built Buses handles eligible documented expenses through its general reimbursement plan on file. Bring prior repair paperwork to the service desk or contact DTNA customer service at 1-800-547-0712.
| Reimbursement | Reimbursement available |
|---|
Timeline
| September 27, 2019 | NHTSA published the recall |
|---|---|
| November 19, 2019 | Owner notification mailed |
| November 25, 2019 | Dealer notification began |
| November 25, 2019 | Dealer notification ended |
| November 25, 2019 | Interim owner notification (was planned for this date) |
Frequently asked questions
What is recall 19V686?
Recall 19V686 covers 618 2017-2020 Thomas Built Buses Saf-T-Liner C2 school buses with Detroit DD5 engines and Allison transmissions. The Flex-Plate/Torque Converter fasteners were not tightened enough. Dealers will inspect and tighten the fasteners as needed for free.
What should I do if my 2017-2020 Thomas Built Buses Saf-T-Liner C2 is on this recall?
Check your VIN to confirm your specific bus is included in recall 19V686. If it is, contact a franchised Thomas Built Buses dealer to schedule the fastener inspection and repair. Reference recall 19V686 and DTNA recall FL-828 when you call.
Is the recall repair free?
Yes. Federal recall law requires manufacturers to repair safety defects at no cost. Thomas Built Buses dealers will inspect and tighten the Flex-Plate/Torque Converter fasteners as needed for free under recall 19V686.
What is the safety risk in recall 19V686?
The safety risk is a disabled school bus in traffic. NHTSA campaign 19V686 states that loose bolts can leave the bus disabled and lead to a school bus evacuation in an uncontrolled traffic situation, increasing the risk of injury.
When did the recall repair start?
The recall repair began November 19, 2019. Owners with an included bus can contact a franchised Thomas Built Buses dealer for the inspection and fastener tightening. DTNA customer service is available at 1-800-547-0712 for recall FL-828.
More information
| NHTSA campaign page | nhtsa.gov/vehicle-recalls/19V686000 |
|---|---|
| Thomas Built Buses customer service | 1-800-547-0712 |
| NHTSA recall # | 19V686 |
| NHTSA recall # (full) | 19V686000 |
Source documents
-
Download Misc. Document (PDF) - Download Recall Investigation Document (PDF) (PDF)
- Download Owner Notification Letter (PDF)
- Download Recall Report (PDF)
- Download Quarterly Report (PDF)
- Download Recall Acknowledgement (PDF)
This article is generated from NHTSA's primary recall filings and reviewed against the source on May 23, 2026. RecallNotify does not paraphrase NHTSA's consequence language; that text is reproduced as written above. Editorial standards →