I ordered some LT71141 fluid and duly received some golden fluid which I put into the transmission. I needed some more, so called a local Motor Factor and having given the reg number of the car, received some RED fluid. Upon querying this, I was told just to return it for a credit.
Now, I've tried to order some more fluid elsewhere, but on the online spec sheet it says it is red too. I called the vendor, a large independent oil and lubricant blender, and was told the red colour is just the dye the individual supplier uses, it makes absolutely no difference and I can add it to the gold stuff with no worries, so long as it is the same spec. What's the verdict here?

I have read back through various threads arguing the types and manufacturers of fluids, but no mention of colour? Is it important, or am I being picky? Is it just a difference caused by dye? Why wouldn't a supplier just leave it golden? The stuff I sent back had no mention of LT71141, it was matched to the car via the reg plate, but this stuff distinctly says on the bottle (albeit BMW) 71141. I really could do without making one of those "Oh no, you didn't do that, did you?" mistakes (again!)

 

I don't know if you were right or not, but I think you were wise. I wouldn't mix a red fluid with a golden fluid, regardless.

Personally I use only ZF Lifeguard 5 for my ZF5HP24 transmission, yep, I know the Mobil LT71141 is its equivalent, but I stick with Lifeguard 5.

 

Well, I've phoned a couple more wholesalers this afternoon and the consensus is that there is no problem - so long as the fluid is the correct spec. So why spend money sticking red dye in a golden fluid?
Apparently because golden fluid doesn't stay golden very long, and soon looks like dirty engine oil. If you have a pool of fluid under your car, it's pretty easy to identify where it's from if it is red...

 

Exactly the same reason red dye was originally added to ATF 75 years ago, to easily differentiate it from engine oil. If it meets the LT71141 specification, it doesn't matter what dye is in it.