Sorry for the delayed response. so the gear case oil is turning black or the tranny oil, still confused. In any event what are the hours between the color change and what fluid/oil are you running?
Have changed it out 3 times. The first time it smelt like it may have gotten hot, the last two times it just looks dark. I'm wondering if what I have is a spun bearing and it is cast iron in the transmission fluid. I think I will change it again and send it out for oil analysis.
A follow up. A noise was being generated from the same Vee drive area at low RPM so we had a vibration analysis done to determine where the noise was coming from but due to the solid construction of both the Vee Drive and the transmission it did not identify the source. We sent the Vee Drive out for a rebuild which was completed but the repair shop indicated the Vee Drive was in pretty good condition as was. We then sent the paragon transmission out for a rebuild and it was in need of a rebuild which they did. After the units were reinstalled the noise was still there. It turns out the hydraulic pump in the transmission was not putting out enough pressure at low RPM. (around 500 RPM) The repair shop indicated that they could no longer get parts to rebuild the hydraulic pumps in these transmissions. If I keep the RPMs over 700 the noise goes away which is a good short term Band-Aid, but I need to find a more permanent solution.
I'm guessing the black colour in the vee drive oil was likely caused by better detergents in the new transmission oil after an oil change on my last preventative maintenance oil change. Has anyone found another hydraulic pump that might work for these old paragon PV32-R transmissions?