Mixer walked off the counter and bent the shell housing... Mixer works but is squeeking and has loose nuts inside...How do i open it up?

Some ...what you may consider silly stuff...
1 check the outlet that you are plugging your mixer into it may be bad. Not the wire but the plug in the wall may be bad, plug a hair dryer in on high if it runs for 60 seconds it ok.
2 check the plug of the mixer make sure it is not bent at the wall pins
3 open the rear of the mixer by removing the round cover at the rear of the mixer look for loose wires, sometimes the socket connectors on the speed switch break off.
4 there are three screws on the speed control switch that control the mixer, sometimes after time these screws can actually turn due to vibration and the mixer will just not start....so.....start with the top right screw and turn it counter clock wise a quarter turn and start the mixer if it starts even for a half a second then the problem is in the switch. and your only problem is the proper timing set by the three screws.
5 gears inside the mixer can strip and freeze the motor so nothing turns...put your ear next to the machine mid way and turn it on ...if you hear a hum from inside then it is a gear problem.
6 If your machine is older then 1978 then it may be the IR filter inside the mixer (hard to find )
7 the carbon brushes that are located on the side of the mixer may have finally worn down (cheap fix) but there are four ways to put the new brushes into the machine and only one way works. You have to be careful with the beveled edge of the new brush and which way it fits back into the housing.
8 Now you are inside the mixer if everything else fails, the motor is the next step and it will require a full tear down, to repair, there are two parts the armature and the winding and each will take about thirty-five bucks to get and either or both will take about 2 hours to repair but if you go all the way down then you need a new gasket and gear grease clean and re-pack too. At this point you are performing an overhaul . let us know if this helps.

The speed control lever is either bent or the screw it pivots on has come loose. The only way to solve the problem properly is to take off the back cover, remove the white and the black wires from the speed control plate, remove it from the pedestal (1 screw up inside the pedestal to remove hinge pin), take the chrome drip ring off, remove the planetary and remove the 9 screws holding the 2 case halves together. That will allow you access to the lever and you will be able to tighten the screw or remove and bend the lever to give it more tension on the bumps in the housing that hold it in off or speed positions. This list is pretty much in order of how you do it.

That is usually caused by a stripped gear. It is hard to give you a good idea of what to check without a model number.
If it is a 4.5-5 quart regular mixer then it will most likely be a bad worm gear:http://www.mendingshed.com/kawormgear.html This would be a fairly easy repair. You will also want to check the other gears to make sure they are not damaged.
However if it is a 5 or 6 quart Professional mixer it will be more involved than that. You will want to take the mixer apart, inspect each gear (you will need to clean off the grease). Any gears that are worn damaged or nicked will need to be replaced. Also check the bearings, and the retainer pin. If these are bent or damaged they may need to be replaced. While you are in the mixer check to see if the transmission housing is cracked, if it is replace it with the new metal housing. If all of the above are in good shape check your planetary assembly, it is pressed together and could become loose causing the same issue.
Please let me know if you have any questions.

You may be correct about a loose spring. Check this:

Carefully lay the mixer on its back side to access the bottom of the mixer. Remove the cover screen covering the opening in the bottom of the mixer. Using an extension and appropriate socket, be sure the nut of the bowl lift rod is snug, slightly compressing the spring of the bowl lift rod.

More likely the pedestal base is bent. Your local service agent has probably seen it before and should be able to bend it back flat again. It's a brutal process with a heavy soft hammer that you probably won't want to see.

Remove the whole planetary from the bottom... There should be a large nut on the main shaft...remove it ....whole assembly drops down...careful...don't drop it......At the top of the bent shaft you should see some center punches holding a thin nut in place.....drill them slightly so you can loosen the nut. There are some studs that hold the lower bushings in place...remove them with a straight blade that fits the screw snug. You can have a new shaft made out of stress proof steel shafting from a competent machine shop........MONSTROSPIZZA.COM

It sounds like either your main shaft nuts are loose in which case you can tighten them up. Tighten the bottom planetary nut first then draw up the main shaft with top side nut but not to much. Its possible to overtighten this. You tighten the top until you feel it getting tight then back it off a little. Otherwise you can pinch the gears and everything tight to the shaft by over tightening and your shifter speeds wont work right.

Or If thats not it, Has the transmission been apart recently? Its possible to put that top gear in upside down which will lock it up when turned on. and break additional parts. I'm talking about that two part gear assembly that has the spring loaded diving key in it. Match up the wear points. you should be able to tell which way is up by the wear on top or bottom of that gear.

Hope that helps!

It sounds like your mixer likes to take a beating, ive never dropped one and for good reason, they weigh quite a bit. first check to see if all the rubber legs on the bottom are still there. if they are the only possible solution to fix it after being bent or warped is to either re-shape the part using a tool strong enough to do the job, or to replace the parts needed. the hinge pin part number is 16910. is the base is bent the part number is 240151-1. If the lower portion of the mixer itself is bent or warped this is a serious problem and will require you to dissassemble the entire unit. part number for the lower gearcase is 240350-4 Please not that all the parts list are white in colour. hope this helps.

Thanks

Some of the oil has separated from the grease inside the transmission, the grease should be replaced. You don't need a total dismantle,. simply remove the top cover and the transmission housing. Remove as much old grease as you can, then replace it with grease from Kitchenaid Parts, or locate a Shell Oil distributor in your area, you want Shell Darina XL EP-2. The oil that came out of your unit probably won't be enough to do immediate damage, but because it's separating, it's becoming less effective. It'a messy job to remove it but will add years of life to your mixer. If you find this solution helpful, please rate it. Good luck. ricardok45

I had this happen while I was finishing my Christmas cookies. (note: unplug the mixer!) After reading some other posts, I undid the screws on the back of the mixer and removed the plastic parts to look at the inside. The nut on the bolt that connects the stand to the mixer body was really loose. I used a set of needle nose pliers to tighten the nut to the locking washer. Once I did that the button to release the body worked just fine! I put the reassembled the back parts and plugged it in to make sure it worked. There were 8 screws I had to take out before I could remove the knob assembly and get to that bolt and nut. Hope this helps!