Jurking, limp mode,weird noise on gearbox or trans

My toyota alphard 2015 2.4 engine. Just both 4 months ago. Suddenly having problem on I think transmission or gearbox. When I drove it, suddenly accelaration going down on its own like no power or trying to accelerate it but only rpm move not the car. . When I stop and start the car again I heard weird noise like string or metal rumbling inside and check engine came out. I try to run in again and it starts jurking on lowgear and wont go up just stay on 2000rpm. But when I got to the garage all sudden it return to its normal drive. But when I try to drive it a long ride sudden change gear on 2000rpm. I think its on limp mode already. Now I dont want to run the car because of what happen. Do you know where can someone fix it and whats the problem of my alphard? Here is some share video that I have. Is the first start of the car also is normal noise? The second one noise is not good already.