I would put the front on jack stands, drain, refill, and bleed the power steering fluid per https://www.newtis.info/tisv2/a/en/e...g-unit/DsV56Jq.

There's also that Lubrizol 6178 - Pelican has it - that you may want to try if you're up to it. Here's a thread you may want to go through.

https://xoutpost.com/bmw-sav-forums/...g-fluid-4.html

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'05 E53 X5 4.4i, '97 E39 528, '07 E92 335i, '16 F86 X6M.