The 42054 is somewhat old news, but with this year's 42102 refresh, I thought it was a good time to go back to my previous attempt of adding RC steering & drive. More than one of this mod already exists, but I had different goals. While the existing mods tend to heavily modify the internal structure, I wanted to preserve it, and most importantly, keep intact the steering mode selection mechanism & cabin rotation mechanism, which I personally find to be among the best of any technic set. I also wanted to preserve the side-panel switches. The entire mod use very few extra parts, probably less than 100.
I do not plan to make instructions, as I'm using MLCad and its single-threaded software renderer makes it unusable on models above ~1000 parts. But I'm uploading a bunch of pictures, for those interested, or to give potential ideas to other modders.
Summary of changes:
Removed inner gearing that controls tool shaft & cabin rotation, to make space for a servo-motor that replaces manual steering.
the M-motor is moved up to the cabin, in place of the manual steering mechanism. There's also a clutch gear now (the original design uses two clutch gears for the tool shaft and none for the cabin - it seems like a mistake)
XL-motor takes the place of the M-motor, feeding into a 2-speed LO/HI gearbox, then to all wheels (4x4).
Both axles now have differentials.
Battery box moved out as a tool-attachment, to the back in order to balance the overall weight. Otherwise there is much too much weight in the front.
IR-receiver takes the place of the battery box, under the hood, poping out where black stripes used to be, making it nearly invisible.
One of the side panel's switches still control the cabin rotation, while the other controls the LO/HI gear switching.
I've only decided to add a gearbox later on, and there wasn't enough horizontal space left to secure one end, it's only supported vertically by other gears. Because of that, there's gear clicking when the tractor starts to move.
the rear tool shaft is gone, and the front one is coupled to the drive, i.e. it only functions when driving.
the original cabin rotation uses a heafty 25:1 speed reduction, which I couldn't achieve in such little space up in the cabin, so it's 2.8 time too fast.