My car isnt working... I have no idea what is wrong with my script.?

I made this script and the car doesn't move. I looked at the motors and noting is happening. They just sit there, even when my script trys to change it.

local rm = script.Parent.FrontAxle.RightMotor
local lm = script.Parent.FrontAxle.LeftMotor
local seat = script.Parent.VehicleSeat
local maxspeed = 90



local function onChanged(property)
    if property == "Throttle" then
        lm.MotorMaxTorque = 20000000
        rm.MotorMaxTorque = 20000000
        lm.AngularVelocity = 200
        rm.AngularVelocity = 200
        seat.Torque = 500000
    end
end
seat.Changed:connect(onChanged)