Peterbilt replacement engines & transmissions
Peterbilt Truck Engines & Transmissions
Peterbilts have run PACCAR, Cummins, Caterpillar and other engines depending on model and era. Send us your VIN and engine details and we search supplier sources for a used unit that matches.
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 Peterbilts
Newer Peterbilt highway trucks such as the 579 and 567 are commonly built with PACCAR MX-13 or MX-11 engines, and Cummins engines like the X15 have also been widely offered. Older models such as the 379 and 378 often ran Caterpillar C15 or C13, Cummins ISX or N14, and some Detroit Series 60 engines.
Medium-duty Peterbilts have used Cummins mid-range engines and PACCAR PX engines. Your VIN and engine tag confirm what your truck was built with.
02Transmissions
Peterbilts commonly run Eaton Fuller manual transmissions, the PACCAR TX-12 automated manual in many newer trucks, and Allison automatics in many medium-duty and vocational applications.
03VIN, engine serial and build sheet
Peterbilt build data tied to your VIN lists the original engine, transmission, axle ratios and options. The engine serial number pins down the exact engine version and emissions period. These details matter because two trucks with the same model number can be built very differently.
04Glider kits, swaps and packaging
Classic Peterbilts are often repowered, and some older-style trucks were built as gliders. If your truck has a different engine than it left the factory with, tell us what is in it now. Engine mounts, cooling, wiring, ECM and any aftertreatment need to suit the engine you are installing.
05What to have ready
Before you call, gather:
- Full VIN
- Engine model and serial number
- Transmission model, serial and BOM if needed
- Truck model and year
- Whether the truck has been repowered or is a glider
FAQ
Peterbilt engine & transmission questions
What engine is in my Peterbilt?
Check the engine tag or the build data tied to your VIN. Newer Peterbilts often have PACCAR MX or Cummins engines; older ones commonly have Caterpillar or Cummins.
Can you find a Caterpillar C15 for my 379?
We can search for one. Caterpillar stopped building on-highway truck engines years ago, so units come from the used market. Send your engine serial so we search for the right version.
Will an MX-13 from a Kenworth fit my Peterbilt?
Kenworth and Peterbilt are both PACCAR brands and often share engines, but emissions year, ECM and installation details still matter. We match by engine serial and VIN.
My Peterbilt is a glider. Can you still help?
Yes. Tell us what engine and transmission are in it now, along with the VIN and serial numbers.
Are you a Peterbilt dealer?
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 Peterbilt? 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.