Trans fluid should be red colored, not brown. When it is black, it is burnt and bad. You can't get it all out unless the system is flushed. It was probably burnt before the last change, so the leftover bad fluid in the system colored the new red fluid brown.
The actual OEM fluid from the dealership is about the color of a light beer. Very light yellowish and clear. more like piss... A lot of other producers make all sorts of colors, but color doesn't matter. What matters is if it specifies that it is recommended for a ZF 5hp19 (or whatever specific transmission you might have) transmission. Go to the ZF website and look it up yourself, because most auto parts stores are more out to sell you anything they can, or they just don't know or care or have bad info. I tried to find a link to the PDF on the website, but my computer and my phone are acting up right now. Just go until you find the ZF website and download the correct info yourself. The specs are...ZF S671 090 170 (lifeguard 5 ) or VAG / VW 052 162 A1/A2/A6. Different brands of fluid can be mixed as long as these fluids are as specified by SPECIFICATION NUMBER REGARDLESS OF COLOR. Mixing isn't an issue.
If mixing was an issue the manufacturers would recommend you flush the old fluid out of your TC when you change the fluid and filter for warranty reasons. The lifetime fluid stuff is a myth unless you find out the hard way that your transmission get's roasted when your transmission fluid wears out, yeah...lifetime fluid...They claim it's not volatile too (evaporates) , but if it wasn't, you wouldn't be able to smell it.
Take the fact that you can smell it and realize in order to smell it that itty bitty particles of it have to go up into your nose and come into contact with your olfactory bulb up in your head between your eyes. Add on increased volatility when heated and it's obvious life-time fluid is a myth to sell you a new car or a new transmission
