Mercon 3 Instead Of Mercon V 97 4.6 GMQ

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Apr 13, 2009
Miami-Dade County
My friends wife couple of week ago let Jiffy Lube service the ATF in their 97 Grand Marquis..They put in Mercon 3 instead of the Mercon V..Now he says the car is shifting erratically..He told her awhile back never to take the car to Jiffy Lube for anything but that fell on deaf ears..Has the Mercon 3 damaged the transmission? He bought the car last year from a private owner [150K miles] who only serviced the car at the dealer..The private owner bought the car brand new..All maintenance [including fluid changes] was up to date when he bought it..The car had zero issues before it went in to Jiffy Lube..The car now has 180K miles on it.
duh Cant JL do anything right????? As for Mercon 3, I dont know much about transmissions, but it sounds like they need to have it looked at and have the fluid changed to Mercon V
Where did they get Mercon 3 ? I don't think it exists. There is Dex III, and Dex/Merc, and ATF3, but as far as I know there is only Mercon and Mercon V. Yeah, time to do some drain and fills QUICK! Perhaps pull the coolant line and pull it out that way? I have gotten Mercon V from Walmart that was open 24 hours a day before for an emergency fix. If they need that car tomorrow that is where I would start. The Supertech stuff works pretty good in all the applications I have used it in. (99 F150, 01 Taurus, 02 Taurus, and 04 Taurus) The SuperTech Fluid is something like $4.49 here. Other house brands are similar. It's a good starting point if this is their daily driver. Abandon all hope he who enters Jiffy Lube. I'm not sure they can read a dipstick properly much less take the time or effort to read a owner's manual. Good luck with your friend's ride.
Originally Posted By: SuperDave456
Where did they get Mercon 3 ? I don't think it exists. There is Dex III, and Dex/Merc, and ATF3, but as far as I know there is only Mercon and Mercon V.
They wrote Mercon 3 on his bill [I never heard if before either] but in real small print they wrote Dex-Merc. I already called him and told him to take it out immediately. Thank you everbody for your quick response!
Isnt it amazing how a company that makes a decent oil product,cant run its own oil change locations for beans.Just goes to show,you should stick to what you know and dont try to do everything just to make money.
No such thing as Mercon 3. Never was. No such thing any more as Dexron-III or Mercon, but there used to be, and the formula might still be made (or a universal that is close enough). (I know, there is real Dexron-III made under the Allison TES-389 spec.) Anyway, for this transmission, the poorly trained guys at Iffy Lube put in the wrong stuff. And they probably don't have the right stuff. MerconV is clearly the right fluid, although adding a bottle of Lubegard green or platinum ATF supplement will likely fix the fluid that's in there.
Was the tranny refilled to the correct level? Too high or too low can often lead to strange shifting problems. Check the manual for the proper checking procedure (hot or cold) and go from there. FWIW--Oldtommy
He took the car to a transmision shop that also works on the 4.6 county cars..They put in the correct fluid [Mercon V] and added platinum ATF supplement..Hopefully all is OK. Thanks all for your help.
I thought Mercon V wasn't even invented until '98, so wouldn't plain Mercon have been the "correct" fluid for a '97? I know Ford back-spec'd Mercon V for all 4R70W and AODE applications, but I don't see why using plain Mercon in a transmission that originally called for it should have been a problem.
Whats up man, You might want to check the manual I don't think that car called for mercon V until 1999. So I think the car was ok. I've owned a few of the big body fords from the mid 90's and they all called for mercon.
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He stopped by the Ford dealer and spoke to a few of the techs and the head of the service department before he went to the tranny shop..They told him to use Mercon V..So far [about 150 miles since the change to Mercon V] everything seems back to normal. We really do not know for sure what fluid J.L. put in there.
FWIW, there's a guy on another forum who SWEARS there is such thing as Mercon 3, and claims to have a bottle of Motorcraft Mercon 3. I've confronted him about it several times and he nevers provides proof though.
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