What you'll need : A donor manual car, no ways around it unless you wanna spend thousands at the wreckers...
While you're in there i'd recommend getting a new clutch and pressure plate, new slave cylinder and new axle seals since you'll have the transmission out.
And a bunch of tools!
I won't go into excrutiating details so if anyone needs more info on anything feel free to reply and i'll do my best to explain better!
So my automatic cube had a push to start key and automatic hvac, whereas my manual had a normal key and cable hvac, you will have to swap those over if you're in the same situation...
So here's what's different between the cars and will need to be swapped over:
Transmission (duh!)
Shifter and cables (you can pop the cables off the transmission by prying them off, it's a ball and socket)
Axles,
Flywheel/clutch/pressure plate assembly,
Passenger side axle to engine mount,
Thermostat housing and water pump housing (or just put bolts and clamps in the transmission water cooler hoses),
Hydraulic clutch system (slave, master, tubing and dampener)
Pedals assembly,
Shift boot,
Instrument Cluster,
ECU,
BCM,
Dash harness,
Hvac box,
Brake master cylinder reservoir,
Engine harness,
Front chassis harness,
Probably other stuff i forgot :')
Before you start, you'll want the AC Refrigerant removed from both cars if you have a different hvac setup (electronic or cables), i will assume in the thread that the manual has cable hvac and the auto has electronic hvac. Along the process you'll see a bunch of electronic modules, you will wanna replace all of them from the auto to the manual ones, some are vin locked and i don't know which ones so personally i just replaced all of them!
Let's start with the mechanical part!
The transmissions obviously have to be taken out on both cars, start with the battery, battery box, airbox, then the axles (just need to undo the shocks from the spindles to get them out), and after disconnecting the clutch hydro hose, harness connections, transmission mount, torque mount and shifter cables you should be ready to unbolt the transmission and get it out, don't forget the starter bolts, but the starter doesn't need to come out on the manual, but the torque converter bolts are accessible from the starter hole on the automatic (it's the same starter auto or manual)
Support the engine with a jackstand or something before dropping the transmission mounts.
At this point you can put the manual trans back onto the engine and bolt the supports back in, but i left it out until the shifter was installed, to have the space.
The brake master cylinder reservoir has a port on it to feed the clutch master, so pull the spring pin on the center bottom of the reservoir and swap them over.
Nissan in it's infinite wisdom decided the shifter would come in from the bottom for some reason, so to remove it you'll have to remove the front part of the exhaust, undo the spring bolts from the manifold, the flange after the cats and the o2 sensor connection, once all that's out pull the heatshield, it's held with 5 spring clips including one under the insulation on the firewall, once all of them are out according to nissan you'd have to drop the subframe but i just bent it to remove it and bent it back to shape to install it.
Now that the heatshield is out, you can pull the console between the seats, remove all 4 shifter bolts and the shifter is held on to the floor with plastic clips, pry those a bit and it'll come out through the bottom, route the cables over the sway bar as it was and you'll be ready to install it the same way on the other car.
Once the shifter is transferred, and while the transmission is out of the way, it's time to do the wiring, so let's start inside the car. You'll want to pull the whole dashboard eventually, so might as well do it now and have the space to work!
To remove the dash there are a bunch of trims to remove first (knee panel, around steering wheel, in front of the console, etc.) then you get access to a bunch philips screws and 10mm bolts which are holding it to the bottom of the framing, the side in the fuse panel on the left side and blank panel on the right side, under the a-pillar trims, under the hvac and radio trims, and there's a 10mm under the light sensor trim near the windshield on the right side.
The glove box needs to be removed to access the passenger side airbag, it's held in with two 12mm screws then you just push it up and it'll come out pretty easy. Store it facing up, somewhere safe.
The instrument panel needs to come out (just pull on the trim then undo two philips head screws) and there are more screws under there. Once all that is out, you should be able to lower the column and pull the dash out, just wiggle it and see where it's catching, there's always a screw hiding somewhere that you forgot to remove (or that i forgot to mention)...
The steering column is a choice, you can either cut slots in the faceless bolts holding the lock cylinder in and swap them around, or swap over the whole column, i did the latter cause i liked my black steering wheel with the beige interior, so i figured i'd do both at once and just swap over the whole column. It's held in with two slotted inserts held with nuts, one bolt at the joint behind the pedals, and one bolt where it tilts up and down, then it should just come out (careful not to turn it or you can mess up the clock spring)
To remove the dash frame, you got a few bolts inside the door jambs, on the bottom of the hvac box, some holding the hvac box itself to the frame, and one behind the wiper cowl (remove clips and wipers to access). On the right side of the dash, there are lefty tighty screws you'll need to righty loosen to remove tension from the tubing to the chassis, once there are all the way in, the dash tubing will come out!
So at this point from the manual car, you should have the manual transmission, shifter assembly, brake master reservoir, clutch hydro system installed; and the dash panel, pedals, console and dash harness still removed. Let's go back in the engine bay and start removing the harnesses.
Both harnesses in the engine bay could probably be converted to manual but i figured it'd be simpler and cleaner to just swap them over.
So! Starting with the chassis harness, we're swapping this one over because of the pedal connectors (brake switch is different and clutch switch connections are missing on the auto) start by removing the ecu and it's bracket, then the bumper to remove the bumper there are two 10mm screws in the fender, clips and screws on the bottom to the splash shields and then the sides of the bumper and the grille are just clipped in. Once the bumper and grille are out, remove the trims on the bottom of the headlights, remove the headlights, remove (at least partially) the splash shields, and you should be able to remove the whole chassis harness, starting from the firewall, disconnect all the lights, fogs, markers, abs sensors, wiper motor, and other connectors, eventually it'll come out, but you'll need to loosen the last bolt for the brake booster from inside the car.
Last is the engine harness, we're replacing that one to get the reverse switch connector, and to get rid of all the extra wires from the auto trans (for a cleaner engine bay)
You'll need to remove the intake manifold to get to some connectors, and there's a plate held in with two 8mm bolts on the back of the block with a connector inside, next to the o2 sensor connector. Just follow all the wires and undo a million zip tie clips and eventually it'll come out!
Now that all the harnesses are out, it's time to put the manual ones in! Installation is the reverse or removal, "simply" reconnect everything and the harnesses should keep its shape enough that you'll know where it's supposed to go.
Then once the engine bay harnesses are back in, you can reinstall the pedals, plug in the sensors, and get the dash harness back in, then the dash panel and whatever other part i forgot to mention (battery tray, air box, axles, etc.)
If you have a bunch of weird issues, check your grounds, they're easy to forget, there are two under the intake manifold held with 8mm bolts, one on the passenger side of the engine bay near the relay box, one in the left kick panel (10mm bolt) and three under the dash panel on the dash framing (10mm)
That's it, you now have a reliable Nissan Cube with hopefully low mileage and no rust!
