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The NP273 is the electronic shift-on-the-fly version of the NP271, the heavy chain-drive case behind Ford Super Duty and Excursion trucks and many Ram heavy-duty pickups. The two cases share the housing, the 2.72:1 low range and the 1.50 inch drive chain. The difference is how they shift: the NP271 has a floor lever, the NP273 has an electric motor bolted to the side of the case that turns a double-D shift shaft on command from a dash switch.
When that motor, its position encoder, the wiring or the 4x4 control module fails, the case stays in whatever range it was last in. That might be 2WD in the middle of winter, or 4LO with a truck that binds on dry pavement. A manual shift conversion takes the electronics out of the loop.
Confirm It Is Actually the Shift Motor
Before you convert anything, rule out the cheap stuff. A lot of "bad shift motors" are corroded connectors.
- Check fuses and relays for the 4x4 system first.
- Unplug the motor connector and look for green corrosion or pushed-out pins. The motor sits low on the case and takes road spray and salt.
- Listen at the case while someone works the switch. A motor that hums but does not turn, or does not make any sound with power present, is a motor problem. No power at the connector points to wiring or the module.
- Watch the 4x4 indicator. A flashing light usually means the module cannot confirm the range from the encoder.
Our transfer case shift motor and encoder replacement guide walks through the full diagnosis and what a replacement motor costs.
Conversion vs Replacement Motor
| Option | Pros | Cons |
|---|---|---|
| Manual shift conversion | Nothing electronic left to fail; inexpensive; bolts on in under an hour | You shift at the case or rig your own linkage; dash switch and indicator stop working; possible warning light or code |
| New shift motor | Keeps factory push-button or knob operation | Costs more; the same corrosion that killed the first motor can kill the second; module or wiring faults are not fixed by a motor |
Conversion makes the most sense on work trucks, plow trucks and older high-mileage trucks where 4WD gets used hard and reliability matters more than convenience. If you want factory operation and the problem really is the motor, replace the motor.
What Is in the Kit and How It Installs
Our NP273 manual shifter conversion kit is a five-piece kit: a machined aluminum cover plate that seals the motor opening, a steel lever with a double-D bore that fits the shift shaft, and three socket-head cap screws. Nothing is cut or drilled.
- Unplug the shift motor connector and unbolt the motor from the case.
- Clean the mounting face so the plate seals.
- Fit the cover plate with the three screws.
- Slide the lever onto the double-D shaft.
- With the truck stopped and the transmission in Neutral, rotate the lever to select 2WD, 4HI or 4LO. Feel for the detent at each range.
You can shift at the case, or run your own cable or rod linkage up to the cab. Tie the motor connector up out of the way and seal it so it does not corrode further.
Things People Forget
- Front hubs still have to lock. On Ford trucks with automatic locking hubs that are controlled by the 4x4 system, set the hubs to LOCK by hand before you need 4WD. Shifting the case alone does not drive the front wheels if the hubs are free.
- Expect a dash light or code on some trucks, since the module no longer sees a motor.
- Check the fluid while you are there. A case that has been stuck or binding deserves fresh fluid. Ford specifies Motorcraft MERCON-type ATF for these cases and Ram specifies ATF+4; use what your owner's manual calls for. See our transfer case fluid guide.
- Listen for chain noise. If the case clunks on engagement or whines in 4WD after the conversion, the chain is stretched. The NP273 HV-064 drive chain fits both the NP271 and NP273.
Get Your Super Duty Back in 4WD
Bolt-on manual shift conversion for the NP273, plus the HV-064 drive chain for the case. Free shipping on every order.
Shop NP273 Conversion Kit → NP273 Drive Chain Core Transmission PartsFAQ
Can you convert an NP273 to manual shift?
Yes. A conversion kit replaces the electric shift motor with a cover plate and a lever that fits the double-D shift shaft, so you can turn the shaft by hand to select 2WD, 4HI or 4LO. Nothing is cut or drilled.
Will the dash 4x4 switch still work after the conversion?
No. Once the shift motor is removed the dash switch and 4x4 indicator no longer control or report the case, and some trucks will show a warning light or store a code.
Does an NP271 need a manual shift conversion kit?
No. The NP271 is already a manual-lever case. The conversion kit is only for the electronic-shift NP273 with a double-D shift shaft.
How do I know if my NP273 shift motor is bad?
Check fuses and the motor connector for corrosion first. If the motor has power at the connector and hums without turning, or does nothing at all, the motor is the likely fault. No power at the connector points to wiring or the 4x4 module.
Do I still have to lock the front hubs?
Yes, on trucks with automatic locking hubs controlled by the 4x4 system. Set the hubs to LOCK by hand before using 4WD, because shifting the case alone will not drive the front wheels if the hubs are free.