I tried something new this weekend and I want to check if I understood it right. I own a 2012 Hyundai Santa Fe with about 160,000 kilometers, and I decided to learn a little about my own car instead of only paying other people to look at it. My uncle showed me how to pull out the gearbox dipstick with the engine warm, and I wiped it and checked the oil. It was darker than I expected, kind of brown, and it had a slightly sharp smell. I did not know if that was normal for an old car or a sign of trouble. The car drives fine, but I have noticed a very small delay when I put it from park into drive. My uncle says brown oil is normal and I should not worry. My cousin says dark oil with a burnt smell means the clutches are wearing and I should act soon. After that I read a few pages online about oil colours. One of them was on a Sharjah gearbox website, and I only used it to learn what red, brown and black oil usually mean. If you want to learn more, you can click here on a site like that, but I do not want to rely on one page alone, so I am asking real owners. My questions are simple. What colour should healthy gearbox oil be, and at what point does brown become a problem? Does a burnt smell always mean damage, or can old oil smell like that too? Is it okay to check the oil myself every few months, or should only a mechanic do it? And if the oil looks bad, should I do a full change or a gentle drain and fill first? If you checked your own gearbox oil and found something surprising, please tell me what you saw and what you did next. Thanks a lot.
