Hi,
The owners manual says that Dexron II is to be used in my 92 Legacy's automatic transmission. Is Dexron III/Mercon a acceptable substitute? I have five unopened quarts left over from when I changed the tranny on my 87 GL and would like to use it if safe. Thanks.
Pat Callaghan
92 Legacy L AWD WagonCheck with a parts store if you want to be sure, but Dex 3 is an upgrade of Dex 2, so perfectly useable in Dex 2 applications.
Thanks Ed. That's what I did & they said fine.
Pat
Just a clarification here. You _didn't_ say that an upgrade of a previous specification means it is an acceptable substitute, but some might still infer that from your wording, so I thought I might add a bit. I cannot speak to the transmission fluid concern, but in another fluid, brake fluid specifically, the upgrade to DOT 5 from DOT 4 involved a totally different base substance (5 is silicone-based, previous were glycol-based, and 5.1 is glycol based again), and in some cases this is NOT acceptable to an earlier spec vehicle or brake system. I'm no expert in this area, and others may correct me or add understanding here. I only found out about this because the disc brakes on my mountain bike use DOT 3, DOT 4, _OR_ DOT 5.1, but NOT DOT 5 because the silicone base will not absorb and thus suspend (dispel?) water. If water is not absorbed and suspended, it can lead to localized rust more quickly, particularly in low areas. Collected water can also cause boiling in the calipers in heavy braking, leading to pedal fade. A link to a short article on this is found at
Just a clarification here. You _didn't_ say that an upgrade of a previous specification means it is an acceptable substitute, but some might still infer that from your wording, so I thought I might add a bit. I cannot speak to the transmission fluid concern, but in another fluid, brake fluid specifically, the upgrade to DOT 5 from DOT 4 involved a totally different base substance (5 is silicone-based, previous were glycol-based, and 5.1 is glycol based again), and in some cases this is NOT acceptable to an earlier spec vehicle or brake system. I'm no expert in this area, and others may correct me or add understanding here. I only found out about this because the disc brakes on my mountain bike use DOT 3, DOT 4, _OR_ DOT 5.1, but NOT DOT 5 because the silicone base will not absorb and thus suspend (dispel?) water. If water is not absorbed and suspended, it can lead to localized rust more quickly, particularly in low areas. Collected water can also cause boiling in the calipers in heavy braking, leading to pedal fade. A link to a short article on this is found at
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