Dexron 111/mercon and transmission fluid questions

[Mrshah]

I am extremly confuse here..

what is the different betwwen ATF Dexron 111/Mercon

and regular power streeing fluid ????

I ask for power streering fluid and they sell me

Valvoline ATF (automatic transmision fluid) Dexron 111/ Mercon.

is this ATF Deron 111/ Mercon is good for transmission and also power streeing too ???

1 fluid work for both ??????

[kff]

They spec'd Dexron II but that is an older fluid. It has been replaced by Dexron III that is advanced enough to be compatible with the other ATF called Mercon. So use DexronIII/Mercon in the Power steering/Power Brake reservoir.

[bimmer635csi]

DEXRON-III and MERCON are not exactly the same, but many oil suppliers have found that they can meet both specifications with a single oil. Thus, most ATFs have licenses for both. The only difference between the two is that Ford has one set of tests and GM has another set of tests. If the fluid passes both sets of tests, it can be called a DEXRON-III/MERCON fluid.

In fact, many of the tests in the MERCON test schedule are directly taken from GM's DEXRON-III test protocol. But, it is important to note that all of these tests are only intended for transmissions. However, because ATF is essentially a hydraulic fluid, it works very well in power steering systems. And thus, many OEMs in Europe have taken advantage of this to minimize the number of fluids needed in a vehicle. As well, ATF can be substituted for Power Steering fluid in most instances; however, Power Steering fluid should never be used in a steering system that calls for ATF as the working fluid.

GM just released a new specification called DEXRON-III, H revision. This new specification is backwards compatible to DEXRON-III, DEXRON-II, DEXRON, and Type A ATFs. Oil suppliers are finding it difficult to make some of their fluids meet this more stringent specification while still using existing formulations of MERCON certification.

There's more to know about it. I'll spare your eyes from a lengthy essay. In case you are wondering, I am the co-chairman of the General Motors ATF Committee that issues licenses to ATFs for DEXRON approvals. If you have any specific questions, feel free to ask. I should be able to answer them.

Hope that helps.