Even if the owners manual calls for ATF I wouldn't use it. The manual was printed in 1986. The additives in ATF have changed a lot over that time and have improved for their use which is an automatic transmission. I read about five years ago that the additives had changed in the previous few years in such a way that ATF was no longer good for many power steering systems.

I ruined a pump in my 240D by changing to ATF. The pump started leaking in about 50,000 miles. When I replaced the pump I had read about the use of ATF and used PS fluid from Auto Zone. That new pump has gone about 250,000 miles now and is still perfect, as is the rest of the PS system.

Good luck,