Kenworth replacement engines & transmissions
Kenworth Truck Engines & Transmissions
Kenworths have been built with PACCAR, Cummins and Caterpillar engines, among others, depending on model and year. Send us your VIN and engine details and we search supplier sources for a matching used unit.
Engine families
Engines to check
Transmission families
Transmissions to check
Factory options varied by model and year. Links are starting points, not a fitment guarantee — we confirm against your VIN and serial numbers.
01Engine families found in Kenworths
Newer Kenworth highway trucks like the T680 are often built with PACCAR MX-13 or MX-11 engines, and Cummins X15 and ISX15 engines have been common as well. Older Kenworths such as the W900, T800 and T600 frequently ran Caterpillar C15 or C13 and Cummins ISX, N14 or ISM engines.
Medium-duty Kenworths like the T270 and T370 have used Cummins mid-range and PACCAR PX engines. Your VIN and engine tag confirm the exact engine.
02Transmissions
Common Kenworth transmissions include Eaton Fuller manuals, the PACCAR TX-12 automated manual in many newer trucks, and Allison automatics in medium-duty and vocational trucks.
03VIN, engine serial and build sheet
Kenworth build data tied to the VIN lists the original engine, transmission and options. The engine serial confirms the exact engine version and emissions period. With both, we can search for a unit that fits instead of one that only shares a model name.
04Aftertreatment, ECM, harness and cooling
On newer Kenworths, the engine works with its aftertreatment system, ECM and the truck's electronics. A replacement from a different emissions period or engine family may need different aftertreatment parts, harness changes or reprogramming. Cooling and charge air setups can differ too.
05What to have ready
To get a search started, have:
- Full VIN
- Engine model and serial number
- Transmission model, serial and BOM if needed
- Truck model and year
- Whether you need a complete engine, long block or specific parts
FAQ
Kenworth engine & transmission questions
What engine does my Kenworth have?
Look at the engine tag or the build data tied to your VIN. Newer Kenworths often have PACCAR MX or Cummins engines, while older ones commonly have Caterpillar or Cummins.
Can I swap a Cat engine into my Kenworth?
Repowers are common in older Kenworths, but mounts, cooling, wiring and ECM all need to suit the engine. Talk with your shop before choosing a different family.
Do Kenworth and Peterbilt use the same engines?
Both are PACCAR brands and often share engine families, but installation and electronics details can differ. We match by VIN and engine serial.
Do you source TX-12 transmissions for Kenworths?
Yes. Send the transmission label details and VIN and we search for a matching unit.
Are you affiliated with Kenworth?
No. We are an independent sourcing company. We search supplier sources nationwide and confirm availability and freight on your quote.
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Ready when you are
Replacing the engine or transmission in your Kenworth? Start with the VIN.
Have your engine serial number, CPL and VIN handy. If you don't, we'll help you find them.
Commercial-Engines.com is an independent supplier of used commercial truck engines and transmissions. Manufacturer names, model names and part numbers are used for identification only and do not imply affiliation with, or endorsement by, any manufacturer. Read the full disclaimer.