Application Change: PACCAR → Caterpillar Diesel Swap
Thinking about moving from a PACCAR MX platform to a Caterpillar drop-in? Here’s the practical checklist—what fits, what doesn’t, and what you must confirm before you spend a dime.
1) Fitment: Mounts, Bellhousing, Front Structure
- Engine mounts: Expect bracket changes; verify crossmember spacing and isolator height.
- Bellhousing/SAE: Confirm SAE size and pilot diameter vs. your transmission (Eaton/Allison).
- Front dress: Pulley offsets, fan hub height, and shroud clearance must match your radiator pack.
2) Electronics & Gauges
- ECM family: Your cluster and body controllers expect specific J1939 parameters—plan for adaptor harness or re-pin.
- Tach/speed/oil/coolant: Map sensor types (analog vs. CAN), verify addresses, and confirm DEF/DPF lamps behavior.
- Immob/derates: Pre-clear inactive faults; align VIN/calibration strategy where required.
3) Aftertreatment Strategy
- DPF/SCR footprint and plumbing differ—decide whether to re-use PACCAR ATS or migrate to CAT-era hardware.
- Match NOx sensor styles, doser, and temperature probes so the ECM logic is happy.
- Document DPF ash load and regen history before first fire-up.
4) Cooling & Charge Air
- Confirm radiator capacity, CAC orientation, and hose clocking; pressure test to 20–30 psi for leaks.
- Fan control strategy (viscous/air/electric) must match the ECM outputs or add a controller.
5) Paperwork & Parts You’ll Likely Need
- Mount brackets, bellhousing hardware, adapter harness, throttle/accelerator interface.
- Custom CAC/radiator hoses, downpipe adaption, sensor bungs, exhaust hangers.
- Updated emissions label (if applicable in your jurisdiction).
