Can I safely dissassemble a 74569 motor (the old, fast 9v one) I have an ancient 74569 motor:



Unfortunately, it's broken: The shaft spins freely by hand, but when I connect power to it, it doesn't spin at all.

I would like to see if I can just open it and place a new DC motor inside, but without breaking it if possible – has anyone opened one of these before or posted instructions as to how?

I was thinking something like this motor:



would fit inside it, but of course I would check the dimensions first and make sure it's not a bad solder joint or something else. 

I see Philo has disassembled its replacement here, but I don't see anything similar for the 74569.
Well, I opened it up without much success, and took some pictures of the process:

At first I tried pushing/prying the light grey tabs away from the dark gray "bottom", but those weren't budging



So plan B: wedge it apart:



It was opening, but I was also distorting the plastic in the process - perhaps if I had a hot air station or something, I could have of softened it, but eventually it gave way:



I didn't open it just yet, but rather went to work on the other side - I made my way around from the front/back, as it seemed easier than going at it directly from the side. Anyways, it was much easier than the first side, and I got it open:



Nothing fell out, and I didn't rip any wires out by opening it, so I proceeded to take out the motor:



This is where something finally fell out - there was a little "spacer" disk (visible in the top-left) that was between the end of the axle and the back side of the plastic housing. 

After that, the electrical connection assembly slid off easily - not sure what the component is or how to test if it's good, but it seems like it was made such that it's replaceable - no solder was used, just metal "crimps" 



This is where I found out that the motor itself is good if I just connect a battery to it directly, so I think I may end up drilling some holes and have a DIY wire coming out the back - all the contacts on the inside seemed good and clean, but unfortunately the bottom seems to be rusted to the point of not making contact anymore. 

I think it will snap back together just fine, but it will have scars from the surgery. 

For anyone curious, the motor itself is a mabuchi 70586, but any FC-280 motor should fit.