I am new car user and drove Corolla 2014 model in 3D gear continuously for first 3000 KMS in a normal flat road. Whats the impact of this?

No worries. Your Corolla has a CVT, Continuously Variable speed Transmission. It's smarter then we are.

Thanks. I think CVT is not there in Middle east Corolla model. Its mentioned as GearBox = 4A FYI, am using car from Dubai - UAE. Some of the guys are telling, continuously driving in 3 D gear mode in normal road will impact Car engine and petrol consumption. Please reply.

You are correct, I did not realize you are not in the US I all to often forget this is world-wide. But if it the 4 speed automatic, all you did was not have it in Overdrive, unless there is a 4D on the selector. Yes, in fact you will consume more gas, petrol, but I really don't think you did any damage.Unless you were going 150+kph ..or 90+ mph. Then you may have not allowed the piston rings to 'seat' on a brand new engine. But if you were only going, say, 100kph @ under 3000 rpm no damage You will know if it begins to consume motor oil later. Some people say their Corolla uses some, a US quart every 5000 miles or so, but I can tell you my 2006 Corolla uses/consumes/burns NO oil. None whatsoever.

Can you please check what transmission it is again? I can not find a 4A FYI..there is a 4A engine series, and everything with FYI in it goes to 'For Your Information"..But there is a 4A FI for 4A series Fuel Injection, but that is the engine..not trans. And are we talking about automatic? or manual? Thank You Sir.