Does anyone have a good parts source for the Rear Differential Rubber Boot on the Quattro locking Mechanism?

The part number 017525075A, and was used on almost every Quattro manufactured from 1985 through 1994. My rear differential leaks like crazy with a small crack in the boot. How in the world can Audi quit making a simple part like that which will junk the car if you can't find a replacement?

Thanks in advance

 

The boot is not available but.... You can either buy the whole unit from Audi in a $200 box or you can get this one for about 1/10th the price. https://mercedessource.com/node/1286

Just screw off the fitting at the ends of the shafts and swap them out. Take note of the distance on the shaft on the one for your car. I'm going to get two of these to replace the two on my 5000SQ.