Has ATF ever been the recommended fluid for use in any GM vehicles? My old P/S pump was a groaner, so I bought a replacement. The replacement pump had ATF in it, so I'm thinking it was returned/re-shelved. The replacement pump is also a groaner and Isuspect the ATF did something to the innards of the replacement pump. This particular P/S pump was used on many '85-'91 GM vehicles. I've only used GM brand P/S fluid in the 95k pump and installed it in the new(groaner)pump which will be returned later today. It's been awhile since I've dealt with a P/S pump: should a replacement pump have any residule fluid in it at all? Shouldn't it should be dry inside? It had plastic push-in seals in all the ports, but those looked like they'd been removed/replaced....

 

some cars specify ATF on the cap itself, other P/S fluid .. what does YOUR cap state?

Also, there are several types of Power Steering fluid and ATF.
What is important is that the manufacturer recommendation is followed.

WHY? The seals and hoses and design of the parts inside the pump and power steering box or rack and pinion unit are designed for a specific type of fluid.

If the wrong fluid is used then the seals, hoses will deteriorate and other parts will not perform as they are supposed to and will fail.



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As I posted: I use only GM brand P/S fluid which is the recommended fluid for my Cadillac. I understand the differences in P/S fluid and ATF.So, has GM used ATF in P/S systems? Thanks.....