Transmission maintenance questions
 

The NV4500 has about 20k on it, lubed by syntorq and has a fuller type oil filter at the pto. Had a small leak where the np205 and nv4500 mate. Replaced the tranny/tc gasket and took the oil filter out: both magnets along with the spun cotton-like element were covered in a dirty grey-brown silt like sludge, no metal though.
What is it and is it kinda normal?

Incidentally I found a wix filter 24939 which is a full flow cartridge lube filter to replace the old element in the filter box for a fraction of the cost

Could be water that has contaminated the oil, and then getting caught up in the filter?

X2, make sure your vent is clear