Connection between the motor and the blender unit (where the spinning takes place) - get extremely hot and blender does not seem to blend well. Motor works fine without the top - and the top seems to spin OK when moved by hand.

try rotating the container part 1/4 of a turn to line up slots and press down . then if it does not blend turn another 1/4 turn to line up slots and press down pushing container into base motor unit .
container and screw on blade lid is put in upside down and the plastic posts have to match the base unit to turn on the blender when you press down on container into base unit.

I own and use a ninja blender !.

probably stripped the blender drive off the motor shaft
if it is still under warranty ,take it back
if not , with all the failing units you may get parts from the manufacturer

You have already found what is the problem the blades.
The blades after a lot of working hours with ice they have mainly three problems.
One the sharp adjes have created a lot of teeths and are not so sharp any more so the blending is not smooth anymore.
Second problem they have loose a title so they have move from corect place some milimeters and this change the wave motion and again the beleding is not so smooth as before.
Third the blades are secure on an axis which is located in two bearings which have een wearing out so the rotating motion of the blades again is not so smooth as before.
So if you are not able to fix the blades kit or to find someone in your area to do it profetionaly and cheap one good idea is to buy a new blades kid.
Good luck

Hi! I just had the same problem and actually called the service number that came with the rocket blender. The lady on the phone said that the plastic cup must have expanded (from heat), and to stick it in the refrigerator for 24 hours until the plastic shrinks back down to normal. After the 24 hours the cup should be able to come off. Kind of makes sense, but I hope it works!

This sounds like the black rubber coupler has broken. The teeth often get knocked off. Have a look at the part shown in hte pictures here:
http://kitchenaidblenders.co.uk/Home/tabid/36/p/Two-%282%29-KitchenAid-Blender-Coupler-%2b-WS-Fitting-Tool-9704230_2plusWS/ProductID/175/Default.aspx

Does the motor still work if you take the pitcher off of the base? If so, the rod that's in the blade assembly is probably corroded. The blades are connected to a metal rod that passes through a brass tube through to the piece that makes contact with the motor when you put the pitcher on the base. The grease wears down eventually and if you don't pulse and run the motor for a long time at once, the heat can corrode the bar and cause the blade to stop spinning. You can either disassemble the blade unit, or buy a new blade unit online. google blender parts and you can get one for $10

I need the blend jar for Breville Blender electronic Model BL3. I did not notice that a stainless steel spoon was in the blender. When I switched it on the crossed blade broke off.

your blade assembly is corroded. take it off, and using a rag, grab the blades. using another rag, grab the other end (probably rubber) and turn CLOCKWISE - it's threaded reverse, so you have to turn to the right to loosen, not the left like usual. I had to clean out the rod that connects to the blades - it was all nasty and corroded. I cleaned it with my Dremel and regreased with a tube of grease I keep in the garage, cleaned all other parts with some Dawn, dried well, reassembled, and works almost like new. I'm guessing I ran it too long without pulsing the motor and the heat corroded the rod that's connected to the blades. OR you can buy a replacement blade unit for about $10 online on a blender parts site

you may have stripped the motor gear sek out a new unit

You need the remove the old gray rubber knob. I did it in a barbaric way just hacking at it with scissors. Once you've removed all the rubber, you can use pliers to remove the remaining metal base. Once that's removed, place the new piece on the post and spin it on. Most important, spin clockwise to loosen, not counter clockwise like most items.