So this is a long story, but I will try to keep it simple. About two months ago my 2016 Mercedes C Class started acting strange. At first it was only a small jerk when the car shifted from second to third gear, mostly in the morning when the engine was still cold. I thought maybe I was just driving badly, so I ignored it. Then one day on the Sheikh Mohammed bin Zayed road, the car felt like it slipped for one second and the engine got loud without the car going faster. My heart dropped, I will be honest. I got home safe, but I did not sleep well that night thinking about how much this would cost me. The next day I took the car to a workshop near my area. They plugged in a computer, told me the gearbox was finished, and said I needed a full replacement. The number they gave me was so big that I actually laughed, because I thought it was a joke. Then I saw the man was serious. I told him I would think about it and left. After that I started reading everything I could. I learned that a lot of the time a gearbox does not need to be replaced at all. Sometimes it is the oil, sometimes a sensor, sometimes the valve body, and sometimes the clutch packs are worn but can be fixed. I watched many videos at night and I still do not understand half of it, but at least I now know the first quote might not be the whole truth. I kept typing Quality Mercedes gearbox repair in Industrial Area 10 into Google because a neighbor told me a lot of the specialist garages are in that part of Sharjah. I found a few websites, and one of them had a page just for Mercedes cars that explained different gearbox problems in a way I could follow. It did not fix my problem, but it helped me understand the words the mechanics use, like mechatronic unit and torque converter. Now I feel a bit less lost, but I still have no idea who to trust. So here are my questions for anyone who has gone through this. How do you tell if a mechanic is really checking the gearbox or just guessing? Is it normal to ask them to open it in front of you and show you the damaged parts? Also, how long did your repair take? I use this car every day for work, so I cannot leave it for two weeks without a plan. And did you get any kind of guarantee after the job? I heard some places give three months and some give a year, and some give nothing but a handshake. One more thing that worries me is that I read that a repaired gearbox can fail again if the cheap parts are used. Did anyone here have that happen to them? I am also wondering if I should do a gearbox oil change first, just to see if it helps, before spending big money. A friend said it can make things worse on an old gearbox, and another friend said it is the first thing to try. I got two opposite answers and now I am more confused than before. I am not looking for a fight with anyone, I just want honest advice from people who own these cars. If you have a good story or even a bad one, please share it. Bad stories help me too, because then I know what to watch out for. Thanks for reading all this, and I hope someone can point me in the right direction.