FS25 Realistic 4×4 Traction System v1.0
A dream that’s been years in the making. I’m a long-haul truck driver. Farming Simulator has been my escape between routes for as long as I can remember — but there was always one thing that bugged me, since the very first version I played: the 4×4 system never felt real. It was always just an on/off switch, if it existed at all. No real differential behavior, no automatic engagement, nothing like what actually happens under a tractor when the wheels start losing grip.
I never had the time to do anything about it — until now. Every scrap of free time I get at home between long trips, for the last several months, went into this mod: reverse-engineering how the game’s physics actually work, learning FS25 modding from scratch, testing, breaking things, testing again. I used AI assistance throughout — to study the game’s internals, learn the scripting, and help write and debug the code — and I want to be upfront about that, because I think it’s fair to say so.
This is the result: a 4×4 system built on real differential physics, not a cosmetic toggle.
What it brings:
Real differential physics — front axle engagement and differential lock act directly on the vehicle’s physics, not a cosmetic effect.
Four traction modes, assigned per tractor based on real-world transmission type:
– Manual — you decide when to engage
– Semi-automatic — engages on its own when it detects real rear wheel slip, with manual override available
– Automatic — same principle, for tractors with “classic” automatic systems
– Smart (Fendt VarioDrive) — gradual, continuous engagement proportional to slip intensity, no fixed ratio, just like the real system
– Real slip detection — not just speed-based: the mod reads actual wheel slip to decide when 4×4 should kick in.
– Optional synergy with Variable Tire Pressure — if installed, tire pressure automatically adjusts between field/road mode as the 4×4 engages or disengages.
– In-game adjustable HUD — reposition the indicator right from the game’s General Settings menu, no file editing required.
– Restricted to tractors, trucks, harvesters and cars — stays out of trailers, implements, forklifts, and anything else where it doesn’t belong.
Requirements: Singleplayer only for now (no multiplayer server sync yet).
This is a first public release, built by someone who’s wanted this to exist for years and finally found the time to make it happen. Feedback is very welcome — if something doesn’t behave right on your tractor, tell me which one and I’ll get it sorted.
Changelog
– 4×4 traction system based on real differential manipulation (not cosmetic)
– Functional per-axle differential lock
– 4 configurable traction modes per vehicle: manual, semi-automatic, automatic, smart (Fendt)
– Automatic engagement based on real rear wheel slip detection, with hysteresis and confirmation delay
– Smart mode: gradual, continuous engagement proportional to slip, automatic disengagement above road speed
– Optional synergy with Variable Tire Pressure (automatic field/road adjustment)
– On-screen HUD showing 4×4/2×4 state, traction mode, and differential lock status
– HUD position adjustable from the game’s General Settings menu
– Automatically restricted to tractors, trucks, harvesters and cars
– Initial support for major tractor brands (see DriveModeConfig.lua for the full list)
