I have a problem with the oil priming on the 3.5 LR V-8 in my 1977 military 101 Forward Control. (basically same 3.5 as early Range Rover). For a while it became progressively more difficult to get engine oil pressure at start up. (The engine has under 10,000 original miles from new, no reason to expect anything to be worn out. I have both an electric oil pressure gauge and plus a no-pressure light so it is unlikely both are malfunctioning and I confirmed there was no oil flowing). Eventually the oil pump would not prime at all. The pressure release valve seems free, not hung up, no step or wear issue I can feel. The oil filter is the proper anti back flow type and I changed it (and pre-filled with oil) to be sure it was not defective. The level of oil in the oil pan is fine. Still no pressure. I tried priming by pouring oil down a hose into one of the gauge ports into the pump before cranking with the coil wire removed. No pressure I tried priming by removing the distributor, machining a shaft to engage the oil pump and turning the pump with an electric drill for 15 minutes. No pressure. I pulled the pan and checked the oil pick up strainer. No blockage and looked clean. The oil pan was sludge free. I then bought two brand new gears for the oil pump and installed them packed with vaseline. No pressure. Repacked it again. Still no pressure. I am running out of ideas. I guess when the weather is better I'll pull the pan to see if the oil pickup into the pan is cracked or has come loose where it attaches. The official 101 parts manual doesn't even show the pickup parts, (hard to figure that one other than having been created in the Leyland era of corporate ownership ) but the 3.5 range rover parts manual which is the same basic engine shows a slightly different looking pick up (round rather than rectangular strainer) that bolts on with a gasket, so I suppose it could be sucking air at that gasket or join. Any other suggestions from anybody???