I am restoring a very early Terramite, one that used an L series Gravely as the power source, (T1?). When I bought it, it ran enough that it appeared the pump had reasonably good pressure, so I'm going to try to use it. Is there any source of information about this pump? It's a model TB3 C and there is a K6 stamped above the serial number slot, but no other serial number I can make out. Any info I can get is great, but I would especially like to be sure that I'm using the correct oil. I'm aware that some Terramites used 40 wt. motor oil, and I've seen it said that the earlier pumps were designed to run on automatic transmission fluid.