When driving the VAZ-2101 uphill on high gears (specifically 4th gear), the engine RPM rapidly oscillates/jumps back and forth between 3000 and 4000 RPM. Downshifting to 3rd gear does not fully resolve the issue.
This behavior suggests an instability in the automatic clutch / drivetrain physics model under slope load, causing the clutch to repeatedly slip and re-engage in a rapid loop rather than smoothly transferring torque to the wheels.
Steps to Reproduce:
Enter a VAZ-2101 vehicle (preferably using a gamepad controller with auto-clutch enabled).
Drive onto an incline / small hill in 4th gear.
Apply full throttle to maintain speed up the slope.
Observe the tachometer/engine RPM jumping back and forth sharply between 3000 and 4000 RPM.
Expected Result: Engine RPM should remain stable and slowly drop as speed decreases due to hill incline, prompting a smooth downshift.