Exact family and transmission type
PACCAR TX-12 is a 12-speed automated manual transmission family. TX-12 and TX-12 PRO vocational variants are not interchangeable labels.
Versions and era boundaries
Use the full model/year data sheet and distinguish on-highway from PRO application features.
Published ratings and architecture
Torque, GCW, PTO, direct/overdrive and clutch limits vary by exact variant. Use the data sheet for the exact model; a family maximum does not establish the limit of the installed unit or truck.
Engine and truck relationships
TX-12 is offered in qualified Kenworth and Peterbilt builds, commonly with PACCAR engines; verify the order.
Tag, model-code and software verification
Capture model tag, clutch/actuator service, software, factory build and input-rating evidence.
Integration and later-swap cautions
Confirm engine calibration, axle ratio, driveline and PTO requirements. Later swaps need OEM-level compatibility evidence.
Low-speed, grade and duty-cycle questions
Assess highway cruise, low-speed manoeuvring, soft-surface operation, grade and vocational startability.
Service evidence and road-test scope
Request fluid/service records where applicable, clutch and actuator history for AMTs, control-module fault reports, calibration history and repair invoices. Evaluate engagement, shifts, reverse manoeuvring and warnings in a safe, suitable road test with qualified follow-up for abnormal behaviour.
Reviewed and verification limit
Reviewed September 4, 2026. Torque, gross-combination, PTO and application limits apply only to exact published models and configurations. This page is not a fitment or operating approval.
TX-12 versus TX-12 PRO
Do not collapse TX-12 and TX-12 PRO into one specification. Confirm the exact series, application limits, engine pairing and model year from the transmission tag and PACCAR documentation.
PACCAR integration evidence
Review clutch, actuator, software and fault history with the installed PACCAR engine or other approved pairing. Compare rear ratio and tires with cruise speed or vocational startability rather than judging the transmission in isolation.
TX-12 and TX-18 application boundary
PACCAR positions TX-12 variants for on-highway and selected vocational work, while TX-18 targets higher-torque vocational, heavy-haul and severe-service applications. Verify the exact installed transmission rather than generalizing from the PACCAR name.
Verify the individual truck
Build information, component tags, service records, diagnostics and a qualified inspection take priority over general family-level guidance.
Sources & Technical References
Primary manufacturer and government resources for continuing configuration-specific research.
PACCAR — TX-12PACCAR Powertrain