BMW Power Steering calls for ATF

[325bob]

I just noticed a message on my PS cap "Use ATF only" What would be wrong with PS fluid in a power steering unit?!Did BMW put some A/T clutches in there!?

[BimmerBreaker]

Yes BMW power steering systems use ATF. It's a lot cheaper than the CHF11S they used to put in them

[shogun]

some BMW systems use ATF, for example my E32 750iL with self leveling rear suspension uses Pentosin CHF fluid, the fluid is used for power steering and SLS. If your cap says use ATF only, use ATF. Almost all other power steering systems use ATF as the hydraulic fluid. In a few cases, special fluids were used either for specific climate conditions or so the same fluid reservoir could be used for multiple systems. For example Pentosin (brand) hydraulic fluids were used in some cars. Usually ones with self leveling suspensions require different characteristics.
Power steering fluid is specifically engineered to work with any ATF based system. So if you use power steering fluid in an ATF system, there is no harm done except to your wallet. If you ever add it to one of the special oil systems like CHF, you will need to flush and fill it. BMW E36/E46 Power Steering Fluid Flush DIY https://www.dvatp.com/bmw/power_steering_flush

[325bob]

Yes BMW power steering systems use ATF. It's a lot cheaper than the CHF11S they used to put in them

I can remember when ATF was all there was PS fluid came decades later still not sure why they care and warn you on the cap? I am pretty sure it's not to save you money lol.

[shogun]

The sticker is mainly there, not to mix up ATF and Pentosin CHF. My 750 has a sticker only to use Pentosin CHF, a green sticker is clearly marked on the power steering reservoir cap.
Do not mix with standard ATF as this can cause issues with the power steering system.
Read you user manual http://www.e36.lt/docs/E36_Owners_Manual.pdf page 128 Power steering fluid
With the engine off, unscrew the reservoir cap, then reinsert it. The fluid level should be in between the graduations on the dipstick. Use ATF to top up as required. Your BMW Service representative can provide you with the fluid specifications. Start the engine. Pour in more fluid as required, continuing until it reaches to between the two marks. Switch off the engine. The fluid may rise to about 0.2 inches (5 mm) above the upper mark. Screw the reservoir cap back on.