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Since the "standard" automatic transmission fluid is for Mercon & Dexron specified transmissions, and Mercon V is apparently a better Mercon spec, does it follow that Mercon V can be used in a Dexron transmission?.... or, is Mercon V somehow different?
The reason I ask is that I got a lot of Castrol Mercon V (synthetic blend) on close out, and would like to make use of it in my Buick as well as my Ford. But if there's any question, I would just save it for the Ford.
You are right. I've decided not to use Dexron/Mercon/Mercon V where Dexron is called for, even though the oil companies indicate its OK.
Here's why (from my owners' manual):
"MERCON and Mercon V type fluids are not interchangeable. DO NOT mix MERCON and MERCON V. Use of a transmission fluid that indicates dual usage (MERCON and MERCON V) in an application requiring MERCON may cause transmission damage".
Logically, since regular Mercon and Dexron seem to be similar, I believe one could also say that use of this dual usage fluid in an application requiring Dexron may cause transmission damage. In any event, it's a risk I don't want to take.
I think the explanation here lies in the older friction materials which apparently were attacked by some components of Mercon V. Quite possibly new Mercon V has changed that, but again, there's insufficient reason to take that chance.
MrBSS. Could you tell us what Owners Manual you were quoting from? I have a bottle of Vavoline and a bottle of AAMCO Mercon V. Printed on both is a statment that they a certified for use where Mercon, Mercon V and Dextron III is specified.
Yes, the oil companies all say that, and maybe they're right. I just don't want to find out I got old stock or something, and then try to get reimbursed for a new trans!
My quote is from Ford "Owner's Guide F-150, 2001 Model Year".
MrBSS. Could you tell us what Owners Manual you were quoting from? I have a bottle of Vavoline and a bottle of AAMCO Mercon V. Printed on both is a statment that they a certified for use where Mercon, Mercon V and Dextron III is specified.
The Valvoline "Durablend" ATF that you are referencing is a dual-rated (Mercon/Mercon V) fluid according to Valvoline, not Ford, and in my experience it does not work well in a tranny requiring Mercon V:
Straight Mercon V is now easy to find on the shelves at most auto parts stores (I like Castrol Mercon V - it's recommended and approved by Ford) and is priced competively. So IMO there is no reason to take a chance with a dual-rated ATF fluid if your tranny calls for Mercon V.