AI Damage2021 Kenworth T800: common problems
The maker issued 8 service bulletins for this year. Details by component below, with sources.
Key figures
- Technical service bulletins (TSB)
- 8
Components owners complain about
| Component | Owner complaints | involving a crash | Technical service bulletins (TSB) |
|---|---|---|---|
| Engine | 0 | 0 | 6 |
| Forward collision avoidance | 0 | 0 | 1 |
| Powertrain | 0 | 0 | 1 |
| Other | 0 | 0 | 1 |
Comparison
What to check before buying
- Engine. Cold start, unusual noises, oil leaks and engine codes.
- Forward collision avoidance. Radar and camera: calibration after bumper or windshield replacement.
- Powertrain. Shift quality under load, harsh shifts, transmission codes, CV joints.
Manufacturer service bulletins
Bulletin titles as filed with NHTSA.
- "Kenworth
Dealers should check the chassis list and SIR weekly for VIN changes. 2 chassis added to the chassis list. Peterbilt: Dealers should check the chassis list and SIR weekly for VIN changes. 10 chassis added to the…
- The verbiage in the Introduction section has been updated
- The PACCAR Powertrain Prognostics Webcast video link has been removed
It will be included with updated information at a later date.
- Kenworth - The Warranty section has been updated to include Peterbilt-specific SRT codes for…
Kenworth - The Warranty section has been updated to include Peterbilt-specific SRT codes for cross-division repair filing.
- The attached procedures document has been updated with more detail and explanations
This is not a stand-alone procedure. Cummins Quickserve troubleshooting will specify the use of these procedures while troubleshooting specific fault codes.
- Bogie Crossmember Torque Value Update - Procedure has been updated to correct torque values
- Procedure pictures updated for clarity
When troubleshooting Cummins X15 fault codes 555 or 556, follow this additional testing, inspection, and documentation procedure to help identify the root cause of dusted engines. This is not a stand-alone process but…
- Condition, Chassis Affected, and Warranty sections updated with the following verbiage “E311 must be…
Condition, Chassis Affected, and Warranty sections updated with the following verbiage “E311 must be flagged and open in Service Information Record (SIR) at the time of RO open date to qualify.” Also, “Through Standard…
Other years of this model
Questions and answers
What are the most common problems with the 2021 Kenworth T800?
There are no owner complaints in the NHTSA data for this year; the data comes from 8 manufacturer service bulletins.
How many service bulletins (TSB) were issued for the 2021 Kenworth T800?
NHTSA lists 8 manufacturer service bulletins for this year. A bulletin tells dealers how to diagnose or fix a known issue; it is not a recall.
Should I buy a 2021 Kenworth T800 from a US auction?
Owner complaints describe defects, not crash damage. Before bidding, check the components listed above and review the lot photos: VinWind builds a report of visible and hidden damage by VIN.
Other 2021 models
Read also
Sources: public NHTSA data (USA): service bulletins and owner complaints; YouTube: links to videos credited to their authors. Complaints are owner statements not verified by NHTSA, and describe defects rather than crash damage. Data updated 2026-11-04.