The speedometer (92 500SL Analog Wired) is functioning as though it is stuck sometimes. At times, when auto is first driven, it does not move. Then, after driven a few miles, it suddenly begins to function (unsure of accuracy). Can this be a problem of inadequate lubrication and if so, how do you lubricate it? Also, can the analog speedometer/odometer be replaced with the digital type from same model later year? Appreciate any help with problem.