refer section 17(5) which reads as:
input tax credit shall not be available in respect of the following, namely:-
[a] motor vehicles and other conveyances except when they are used--
[i] for making the following taxable supplies, namely:-
[A] further supply of such vehicles or conveyances ; or
[B] transportation of passengers; or
[C] imparting training on driving, flying, navigating such vehicles or conveyances;
[ii] for transportation of goods;
So this section provides that you can claim ITC on Motor Vehicle when used for transportation of Goods.
Therefore you can claim it if motor vehicle is used for transportation of goods no matter whether you are engaged in transportation business or not