Kenworth · Class 8 vocational/heavy-haul tractor
Kenworth T800PACCAR MX-13 12.9L, Cummins X15 15.0L (also ISX pre-2017)
Built 2000-2026
Engine PACCAR MX-13 12.9L, Cummins X15 15.0L (also ISX pre-2017)
Sources checked 118 of 133 (89%)
What it is
The T800 is Kenworth's vocational workhorse — set-back steer axle, heavy frame, and the ability to carry the biggest engines and the heaviest loads. It does everything from logging to heavy-haul to dump work.
Pick a folder
Fluids & Fill Amounts6 entriesBolt Tightness52 entriesWhen to Service12 entriesWarning Lights & Codes30 entriesHow to Fix It78 entries
The truck itself
Engine options
PACCAR MX-13 12.9L, Cummins X15 15.0L (ISX pre-2017)
Horsepower
405-510 hp (MX-13); 400-605 hp (X15)
Peak torque
1,450-1,850 lb-ft (MX-13); 1,450-2,050 lb-ft (X15)
BBC
115.5 in or 122.5 in
Front axle
Set-back steer, 12k-22k
Radiator
1,440-1,780 sq in depending on engine
Transmission
Eaton Fuller 8/9/10/13/18-speed manual or automated; Allison automatic; PACCAR TX-18 for heavy-haul
Front axle
Dana Spicer 12k-22k (set-back)
Rear axle
Dana Spicer / Meritor 40k-46k tandem or tridem up to 78k
Weight class
Class 8 - up to 92,000 lb; GCWR up to 250,000 lb for heavy-haul
Before you order anything
Options change the numbers
The T800 has a set-back steer axle for a tighter turning radius and better weight distribution. It is built for vocational duty — logging, dump, heavy-haul, lowboy. The T800W is a wide-hood version for high-horsepower applications. Kenworth announced the end of T800 production in 2025; the T880 is the successor.