Madrock, the torquemeters on the Sea King use oil pressure fed from a pump piggybacked onto the No1 MRGB oil pump and supplied from an addition to the MRGB sump at a lower level than the MRGB pumps. The tqmeter oil runs through a union which allows it to flow to the torquemeters only if there is more than 30-35psi in the MRGB system. If the MRGB loses its oil and the pressure drops, a valve in the union shuts and the Tqmeter oil is redirected to the MRGB. The indications that the ELS is operating are a caption on the CWP and the Tqmeter indications dropping to zero. There is another warning if the ELS pressure falls - the most likely reasons being that there is either a hole in the bottom of the sump or that the No1 MRGB pump has failed.
Once in ELS mode you have limited manouverability in order to keep the oil in the lower sump but at 70 kts should have a couple of hours of flying depending on the oil temp. I don't know how long the MRGB will run on ELS without failing but its a whole lot more than 10 mins 47 seconds!