I had a master go bad, and the fluid was opaque, brown. I have only had my truck for 10K of 147K miles and it is obvious what happens if you dont change flush the stuff.

My rear passenger side would not flush, it was probably not working at all before changing it all out. The botton of teh resevoir was caked in black gunk. As I am towing a trailer tomorrow, I am glad to know it is all new fluid.

Sold Truck: 89 DLX extra cab 4x4 22re Automatic/ New truck 97 T100 4x4 auto Sr5