Hey guys, tnx for your replies. But as usual our so called experts check all worst cases before checking the minor things.
I showed it to a guy who tunes racing cars he took 2 days n told check transmission oil n else need to remove the gearbox n see. Then i showed it to a guy at A*W he said the solenoid needs to be replaced (which would cost 20k).
Just before i do what they told, i just downloaded the service manual n checked. To my surprise the blinking O/D error code is for LOW BATTERY POWER. Changed the battery it works perfect.
Well i guess our experts need to look in to smaller details before they dig in. Or maybe they knew n tried to rip me off