No, there is no special reservation for Dalits in Aligarh Muslim University. In fact, there is no reservation for any caste or religion at AMU. However, you need to mention your religion in the application form. After the entrance, the selection list is prepared purely based on merit. 

Although the university does have an internal quota  AMU. If you want to take admission in an MTech course at AMU, your qualifying degree is BTech or BE. You can take advantage of the internal student quota, only if you have completed your undergraduate engineering degree from AMU. 

Some of the other quotas at AMU are as follows.

AMU has reservations for only internal (SC, ST, OBc) and other categories of students, not for Dalits.