TM 10-3930-659-10 2-2.  CONTROLS AND INDICATORS (Con’t). KEY CONTROL OR INDICATOR FUNCTION 47 Engine Oil Level Gage Indicates engine oil level. 48 Engine Primer Knob Primes engine when hot.  Used only when starting engine with JP-4 fuel. 49 Transmission Oil Indicates transmission oil level. Level Gage TA704478 2-8