Thank you for the information on this forum. I successfully changed the pump on my 2011 Leaf and saved $1K allegedly. (I've never brought my car to deal to get estimate.) Especially, given how little value old Leaf is nowadays. This is big saving. I am not a mechanically inclined person. This work took me nearly 3 hours to finish.
My best contribution I can make to this forum is that I bought a compatible pump at much lower price ($126 from Ebay). It works perfectly fine. The part number of the pump I got is 21580-3JV0A. It is designed for 2014 Nissan Pathfinder Infinity QX60 Auxiliary according to the ebay seller description. The pump is the same. The bracket is different. The bracket is secured to the pump with a removable rubber sock around the pump. I removed the bracket and used the pump only.
New pump with bracket
New pump side-by-side comparison with old pump
Old pump Old pump slipped out of the rubber bracket very easily. I didn't even need to remove the pump bracket from the car.
New pump without bracket
Coolant pumped out from reservoir
The toughest part is to disconnect pipe. I ended up just using force. The reservoir container seems to be strong enough. I had to remove both pipes to get enough space to work with.
Reservoir container without pipe.
Metal brackets to clamp around pipe that are both easy and tough to work with.
I tied threads around the pipe clamp when reinstalling so that it wouldn't drop into the abyss of the chassis. It appears to be difficult to fish the dropped clamp out. I liked this hack

even though I've never lost a single one through out the installation. Better be safe than sorry.
I hope this pump will last as long as my car.
Good luck with your ad