Colt Case Ingersoll Garden Tractors

My 4016 has had a slow leak from the travel control valve area. It started sometime after I changed the oil 2+ years ago. I "think" it may be the drain plug. I've tightened the plug but that doesn't solve the problem. Last year I tried pulling the drain plug out, cleaned it off with some brake clean and painted some Permatex 80632 sealant (probably 12-15 years old at this point) on the threads. No sealant was applied to the TCV threads. I wiped the TCV threads clean with a rag and put the plug back in and the TCV still leaks. What would you guys do to stop the leak? I'm not 100% sure the plug is the source of the leak. I plan to try and tighten the hydraulic fittings in the area.

I think I'd go with a quick tighten up of the fittings. Then if it still seems to leak, a good cleaning and figure out where it's coming from. Or just figure it out first and go right to the problem.
Tim