I bought my 2008 Rav4 with the 2.4 a couple of months ago. I changed the rear differential fluid a couple of weekends ago. I would have sworn it was a rear wheel drive, the fluid was thick, black, and nasty. The previous owners must have used the 4 wheel a lot, but there was not a trailer hitch, nor were the frame bolts where it would have bolted up disturbed. They looked factory. Anyway, I did the front differential yesterday. I drove for 10 miles before draining it, so the fluid was about the right consistency for hot gear oil. However, it had a red tint to it. Does anyone know if Toyota dealership gear oil has a red tint? I've never used Redline, so does it? It almost looked as if a bit of tranny fluid had been mixed with it. Any ideas? I replaced it with Lucas 80w-90. The manual recommends straight 90 conv.,or 75w-90 synthetic. ( same as the Haynes book) Are any of the synthetics reddish? I've never used any so I have no idea. I'm just trying to figure out where the red tint came from. I've used many different brands of gear oil over the years, but they have all been about the same color..don't even have a name for it, just gear oil color! Thanks.