Mixing blades detach while being used

Do you mean the beaters? Take a look near the top of the beater shaft. Does it have a slot which holds a wire ring? If the wire ring is missing, that would explain why it won't stay in. Try shopping for a new set of beaters if that's the problem.

http://m.bonanza.com/listings/Mixing-Paddle-Farberware-FTR700-Bread-Maker-Replacement-Part-FTR-700/322565077?st_id=35095804

These show up on E-bay all the time.

The blade sounds like it's jammed somehow perhaps simply with some food matter.
Ensure the mixer is not plugged in then try removing the bowl, locking the mixer in the down position and pushing up hard on the blade to try and dislodge it. If it comes free and lifts up then try wiggling and rotating it normally off the mount.
Sometimes with use the attachments can become slightly warped requiring more force to lift them before rotating off the mount.
I once used my own Kitchen Aid mixer with the dough hook attachment to make a whole wheat bread dough. When I was done the hook was a bit bent from the hearty dough. There was also some flour in the mount causing it to jam. Removing the hook attachment proved difficult but not imposable.
Good luck.

Tegan, sorry to hear you tilt mixer head is drooping and causing rubbing problems with the mixing bowl. This should be pretty easy to fix, if you?ve got a small blade screw driver and a small hex driver (or jewelers screw driver). First, do you still have the K45SS Parts List? If not, you can download a PDF version from the KA website. Click on Customer Care>Locate Manuals & Guides> Enter the 6 character model number (in your case, use KSM90P) and select one of the files that appear under Parts List. Turn to page 4 - Case, Gearing and Planetary unit, which shows the exploded view diagram and locate Illus. Nos. 29 & 30. Page 5 lists the parts as Adjusting Screw and Set Screw respectively. What?s probably happened is that over 12 years of operation, the vibrations from your mixer has caused the set screw to loosen and drop, hence the lower mixer head. Both screws will need to be ?adjusted? to move the head back to its original position. Now the problem is removing the head from its pedestal. Turn to page 8 and gently remove Illus. No. 7, Hinge Pin, with a hammer and pin driver. With the hinge pin removed the mixer head and pedestal can be separated and you should have access to adjusting and set screws. I would inspect them for wear and tear, and replace them, if you deem appropriate. It may take a few trial reassemblies to get the mixer head back to the original factory position, but once there, everything should be OK. I hope this helps! Howard, Burke, VA

pour a little wesson oil into the attachment holes and work the release while inserting and removing the attachment. Make sure the unit is unpluged. The oil will lubricate the lock mechanism.

If it is the worm gear then the planetary will stop turning when there is a load on the paddle but the motor will continue to run at the speed you set it at. I'd be checking the carbon brushes, checking that the field assembly has not loosened up a bit and then I would see if the speed control plate adjustment screws are loose. I'd then reset the speed and see if it stays as it should be.

It is going to low down. the adjustment should at the back of the unit.

Using one of the bowls, filled it with hot water up to the shaft and where the paddle is hooked up. Using a cotton cloth, wrap it around the paddle and shaft, let it soak for 30 to 40 min. After 30 min, twist the paddle back and forth to loosen up whatever got stuck inside the shaft and paddle. Put a little of mineral oil so that the paddle will be easily remove and it will just slide out from the shaft. 

I think this link will help you understand what is needed to fix your mixer.

You will need to purchase a gear. Here is link MarBeck should have it.

You may need to replace some grease. Make sure to use a non-toxic food grade grease.