TM 5-3805-254-20-1
NONELECTRIC GAGES - CONTINUED
TA243712
SPEEDOMETER - ODOMETER
Connected by cable and gears to auxiliary transmission. Speedometer gear size, drive axle gear ratio, and tire diameter
play an important part in speedometer-odometer accuracy. Speedometer cable turns a permanent magnet inside a metal
cup. The metal cup is attached to the needle on front face of speedometer. The magnetic field exerts a pull on metal cup
causing it to rotate. A calibrated hairspring counters the rotation of the cup giving an accurate reading by the needle. The
odometer is driven by a series of gears that indicates miles covered.
TRANSMISSION OIL PRESSURE GAGE
Mechanical gage connected to transmission by small diameter tubing. Actual pressure applied to bourbon tube causes it
to straighten. This movement changes needle position in direct relationship to bourbon tube movement.
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