I recently purchased my '86 911 Coupe (my first 911). As part of the initial PM efforts, I replaced the gearbox oil and when I drained it noticed the color was a gray milky color. This seemed odd, since every manual transmission (Audi) I have replaced the fluid on, the draining fluid is dark brown. I thought perhaps the color may have been inherent in that of the previous fluid. As such I replenished the fluid and drove the car perhaps 1000 miles before, flushing and replacing with new. The photo attached shows the color of the draining fluid (same in both instances). In both instances I replaced the fluid with Castrol 80/90, per Bentley. Is this color a sign that detrimental wear (aka imminent gearbox rebuild) is occurring or is this coloring something that can be expected?
Note the drain plug magnet did have very fine metal deposits attached, no alarming amount, but no metal chunks.
Thanks in advance.