Admiral refrigerators are made by the Whirlpool Corporation. Before it was taken over by Whirlpool, Admiral appliances were made by Maytag Corporation.
Not all , I think .
Whirlpool and Kitchenaid are two different brands.
Amana products are made by Whirlpool. Amana was sold to Whirlpool in 2002.
Whirlpool licensed the RCA name and marketed RCA Whirlpool refrigerators from the late 1950s through the early 1990s. RCA Refrigerators are not longer manufactured.
Amana refrigerators were first manufactured in Amana, Iowa. There is still a company in Amana, Iowa that manufacturers refrigerators, but the company was sold to Maytag in 2001. Some Amana refrigerators now have a Whirlpool logo.
Whirlpool, Haier, Kenmore and Norcold all manufacture refrigerators with removable ice holders.
The better of the older refrigerators include General Electric, Whirlpool, and Frigidaire.
Whirlpool owns Maytag so in USA, Canada, Mexico, China of course and other countries. Whirlpool corporation is huge.
Refrigerators are typically factory charged then sealed and there are no access ports to do what you are asking.
A Whirlpool 4396841 is a refrigerator water filter. These are common in American style refrigerators and helps reduce chlorine, bad taste, odor and rust in the water.
The Whirlpool 4396510 filter is required to operate the water dispensers of many Whirlpool refrigerators. The average cost for such as filter can range between $25 - $30 at many retailers including Amazon.