How do I engage the hammer drill function on a miwaukee hammer drill model 5390?

SOURCE: hammer drills Features

There are a few features you may want to pay attention to include: A Depth Rod mounted to the drill lets you know when the bit reaches the desired depth; Variable Speed Selection allows you to adjust the drill for specific jobs. Use high speed for small holes and low speed for large holes; Reverse can retrieve a hopelessly stuck bit; Removable Side Handles give the operator better control in normal use, and can be removed in confined spaces.

SOURCE: hammer drills and rotary hammers comparison

Basically yes. Lower power units are usually titled as "hammer drills." Higher power units, usually labeled "rotary hammers," tend to be larger and provide bigger impact forces. But there are a few differences that are worth knowing: The rotary hammer usually have a chisel only feature, for light chiseling and masonry removal. Rotary hammers also have specially designed chucks that only accept bits specifically designed to fit their chuck. The special chuck on a rotary hammer helps hold the drill bit and prevents it from slipping during use.

SOURCE: Hammer drill will not hammer.

Need a new clutch/tranny. You can find it online - look up tool parts on Google. Tool Parts Direct is a good source. Please rate me

SOURCE: Describe your Dewalt & 14.4V Xrp

Hello. I can help you. Your motor is producing the smoke. Before more damage is done I recommend taking it or sending it to a Dewalt sercive center.

SOURCE: When I was done using the hammer drill to drilling

open your chuck as far as it will go look down inside the chuck and you should see where it has come from ,if that is where it came from it will be right hand thread probably allen key or very small socket