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Power Steering Fluid for a 56? Lube steering box?


Guest gunjeep444

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Guest gunjeep444

Do I just use ATF transmission fluid for the power steering on my 56 Roadmaster? Also, does one lube the steering box itself? I adjusted it some but don't see any place to add oil to it.

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I believe the power steering reservoir cap might have "Use Type A Fluid" imprinted in it?

Before the Dexron family of GM ATF, there was generic "Type A" atf, which was also used for many power steering units back then. GM states that their Dexron fluids supercede the prior Type A spec fluids, but since the early 1960s, GM and others have had specific Power Steering Fluid. It's more about the specs the rubber hoses and o-rings are compatible with than anything else, I suspect.

IF you can find some Type A fluid, you might get a couple of quarts and flush the system--it probably needs it anyway. Otherwise, I'd lean toward the GM Power Steering Fluid for general principles, doing a similar flush job. The GM PSF seems to be of a slightly thicker viscosity and looks a little waxy, whereas Dexron ATF flows like water and is colored red.

This could be more of a judgment call than anything else, with the default mode being finding some Type A atf.

Just some thougths,

NTX5467

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Howdy,

I've owned a '56 with power steering for 24 wonderful years.

When I detailed the engine bay about 22 years ago I dumped in Type A fluid that was easy to buy at that time. I've not added a drop since and the level is "right on the money".

Type A fluid is rather easy to find on eBay in sealed quart metal and composite cans for about $10 a quart. If you really get in a bind, let me know 'cause I've got a few spare quarts in my barn.

Cheers, :D

Bob

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From my understanding the GM Type A is the older trans fluid and each time it was/is updated to a new formula it is compatible backwards meaning Dexron should be able to be used in vehicles with type A, DexIII can be used in older Dexron vehicles and Dexron 6 (the newest) is back usable for all vehicles. It is supposed to be the requirement that the fluids are able to be used back to previous formulas.

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Yes, GM states all of their current Dexron family fluids are backward compatible all the way to the first Dynaflows. Dexron VI is a semi-synthetic fluid and will have a much longer service life than the prior Dexron III. GM is only licensing Dex VI at the present time, although Dex III is still available from many sources (now termed "Multi-Make" by many, so you'll see Dexron III in the fine print rather than in larger print, as in the past).

BUT . . . by the time the first Dexron fluid was released in 1968 or so, GM was already using a dedicated Power Steering Fluid in their vehicles, as was Chrysler. Although many service manuals stated that ATF could be used for "top offs", if there was a leak and kept getting topped-off with ATF, ATF was all that was in the system before long. My experiences have been that when a system should have genuine PSF, it'll seep and leak with ATF in it . . . until the system is purged of the ATF and then the seeps/leaks go away. It all depends upon the type of fluids the rubber hoses and seals in the system are designed to work with.

Considering the marked differences in the base stock and the additive package between Dex II and Dex VI, I think I'd stay with Dex III in an older vehicle. Not to say that Dex VI would not work well in them, just that Dex III would be closer to what had already been in them for a good while--and at less cost per quart.

Some of our associates would advocate using genuine Type A ATF in older vehicles which used that particular spec fluid (that's what it was designed to work with). This orientation has merit just as using an upgraded fluid has its own merits.

Just some thoughts,

NTX5467

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