Hey guys, have a 71 M600 with oil tanks on both sides. The diagram I saw shows the oil fill, low plug and high plug on the left side. Do you put oil in both sides to the high plug? Also I've read that it holds something like 20 gallons of oil. Does it really take that much to fill it? Just picked this up and I got a parts manual with it which says Hydraulic reservoir capacity- 17 gals. Hydraulic/Hydrostatic system- 20 gals. any help would be great. thanks in advance for your time and expertise.