I have answered similar question several times, and repeating the same for you. My sincere advice would be not to directly think of joining good established companies (because it is not easy, many a times, to get the direct placement).

With some experience in small or medium industries, things are going to be very smooth(do not worry much about your initial salary). You can,even, treat that as a 'training period", and "investment". Keep working, while you can also think of clearing the GATE .

There are many many options for a mechanical engineer after BE/B Tech. Many companies are good for a mechanical engineers, a few of them are as follows:

ABB group,BAARC,BHEL,BEML,Bosch group, BNPM, BPCL, Caterpiller, CELHPCL,Coal India Ltd,DRDO,Ford group,GAIL,GSECL,HPCL,Hundai group,IOCL,IPR,Kirlosker group,L&T group,MDL,MECL,Mahendra & Mahendra group,NFL,NALCO,NHPC,NLC Ltd,NTPC,Oil India,OPGC Ltd,ONGC Ltd.Power grid,Reliance groups,RITES,Tata group,THDC,TVS group,WBSEDCL,etc.