87 560 sel

I have read in some places that ATF is incompatible with the PS pumps that MB uses in the 126 cars. I can only assume that the red liquid inside my PS reservoir is ATF and the pump is a bit noisy, especially while turning...

Has anyone else had this problem? How can it be corrected? Does draining the ATF and replacing with PS fluid solve this, or does the whole system need to be flushed? Would this have damaged the pump? Is there a filter in the circuit?

Thanks

ATLD