I just removed the plunge depth adjustment shaft from my 5625, so I'll post this while it's fresh in my mind. First, I found a Y
ouTube video here that shows the process in stop-motion, and that helped. But there is a point at about 0:20 in the video where I wasn't sure what he did next. So here's the process:
1. Remove the adjustment knob.
2. Remove the 4 screws holding the red plastic cover and set the cover aside.
3. Remove the 1 screw holding the electronic feedback module (EFM).
4. Locate the white wire from the EFM to the motor, and disconnect it from its spade lug.
5. Lift the EFM and fold it back toward the power cord and out of the way.
6. This is the point in the video where it isn't obvious what he does. The motor is in two main parts; the upper black plastic part and the aluminum housing below it. The only thing that holds them together, once you've removed the 4 screws in step 2 above, is friction. I took a small rubber mallet and tapped the four ears of the black plastic upward, on an angle, so that I was tapping only the plastic and not the aluminum below/inside it. Proceed around the motor, tapping these four ears upward in succession, and the black plastic housing will start to lift away from the aluminum body. Soon you'll be able to lift it clear.
7. Lift the adjustment shaft out and set it aside.
8. Reassemble in reverse order.
The only tricky part of the reassembly is spreading the brushes apart to allow the motor's commutator to pass between them. I managed it by myself, pulling them back and holding them with two small screwdrivers, but it would be easier with a helper. You should be able to manage it, but an alternative would be to remove the brushes, slide the two halves of the motor back together, and then reinstall the brushes. If needed, Ron Paulk has a video on replacing the brushes here.
Duane