Trojan 1500Z transmission fluid specs???

Hello Everyone! I just bought a Trojan 1500Z at auction. Trying the machine out, the hydraulics seem strong, and the transmission seems fine in first and second gear, but very little power at all in third. I check the dip stick to find it was very overfull and had lots of water in it. I assume the fluid is frothing up in the torque converter with that moisture in it causing third gear to be very weak. First thought is I need to drain and refill with new fluid and see how it acts at that point. I see on a parts manual there is a screen on the transmission as well. I am sure that screen could use a good cleaning at this point with the moisture likely rusting in it and restricting flow. My questions are as follows: 1.) does anyone have a service manual for this machine? I can't find one online anywhere, and I don't know what kind of fluid to put back in this transmission. 2.) has anyone had this issue before and had the problem caused by another issue? I'm curious if I'm overlooking a potentially big problem. 3.) the brakes do not work on this machine. It is air over hydraulic. I assume I should be able to just fill the master cylinder reservoir with fluid and bleed the line. Anything else to know about this procedure on these machines? 4.) is there anywhere you all would recommend getting parts for these? Seems all the dealers I'm calling are gone with the wind. Thanks in advance everyone I really appreciate it as there is very little information online for these machines it seems.