That's what I'm afraid of too.
I did the front diff pinion seal today. Based on the above feedback I started looking if I could mimick the tool with standard extensions and sockets. The tool looks to be a short 9/16 socket with integrated extension piece. So with that in mind I started going through all my 'spare' tools (aka lost in the abyss of shed sh!te
) to see if I could maybe find a short 9/16 socket. Sure I did, in an old Stanley socket set I found a 3/8 drive 9/16 socket. In the end I used that 9/16" 3/8 drive socket, a 7cm 3/8 extension, adapter to 1/2 drive and then another 10 cm extension. Bit of a puzzle but in 1 specific position of the prop this worked. Bit awkward as I needed to rotate the prop for each bolt but it worked.
The trick is that the prop needs to be straight in line with the diff output shaft, in both vertical and horizontal plane. If this is not the case (will never be 100%) the rotation of the shaft is also important: for me there was a window of about 20 degrees where I was able to slip the socket onto the bolt.
The key is that you need a short socket, that's where the special tool is special: the extension is part of the socket which allows a shorter socket bit.
TL;DR you need to find a short 3/8 drive 9/16 socket and some adapters and extensions and it will work in much the same way as the tool described above. The length of the socket is crucial.
FYI if you replace the nyloc nuts (you should!) a 14mm socket may also work I've found.
