Caterpillar Graduate Trainee Engineer interview questions

The interview was of 3 rounds. 1.Apptitue and Technical MCQ test. (which was really hard) 2. GD 3. Final Interview There is no HR round Please prepare well for Technical test. The final interview lasted for around 35mins. They were testing me in my AOI and they tried to ask very difficult questions. My AOI was SOM, they tried to connect questions from SOM to CAD(!!?). I couldn't make it after interview round.