Low undergraduate gpa..engineering ?

What matters for graduate school is your overall GPA, and your Major GPA (the GPA you have in all your mechanical engineering courses). I remember three distinct ways to enter any graduate program in many of the school I applied for: a general GPA of 2.50 or more (on a scale of 4.00), a major GPA of 3.00, or a GPA of 3.50 in the final 60 credits you had taken. This, clearly, will vary from school to school, and you should check with school officials to see how, first of all, they will convert your grades, and second of all, what they require. However, your grades are only part of the application, you are also required to take certain tests, and your letters of recommendation are in fact probably the most important deciding factor for your admission into graduate school.