I just had a 30,000 service done at the local ford dealership, which included an automatic transmission flush and fluid change. When I got the reciept it listed mercon 5 for the new transmission fluid, even though the manual and dipstick say to only use mercon, not mercon 5 or mercon sp. The service manager said that Ford is now recommending mercon 5 because it is a better product, but he didn't have anything (like a TSB) to back this up with. I looked back at several older posts and someone had a link to a FORD website where it specifically says to only use only mercon for my year and transmission type.

I have the 4r100 4 speed automatic transmission in a 2003 v10 2wd. I probably drove about 60 miles with the mercon 5 fluid, and I'm making the dealer put the correct fluid back in tomorrow. Does anyone know if any damage could occur that quickly? Thank you.

 

Well the latest TSB I have is #01-15-7 it is a tsb that states do not mix mercon 5 with any other type fluid . That includes mercon 3 or mercon.
The reason is that the seals can start to swell and leak and also cause driveability and longevity issues with the tranny.
I would get it in writing that they made a mistake and will repair the tranny in the future if you have issues later on .
This is of course that they don't have a later tsb to back the service guys statement.
Just my $.02
Rich

 

Yes get everything in writting. also get the TSB in your hands . Don't let them go against your owners manual without taking full responsibility..Maybe he's right but maybe not esp since we didn't hear about it here.. Let us know


Dick

 

The service manager is partially correct, Ford did recommend switching some transmissions over to Mercon V to help with torque convertor shudders, however this does NOT include the Superdutys. I did a lot of searching on this topic a few months ago and the concusses seemed to be that Mercon V is not good for this model transmission. Do a search on this forum, if I remember correctly someone else had the same problem with a dealer. When he confronted them they towed it back to the dealer and changed the fluid back to Mercon.

 

I did see that post. They're going to change it back in the morning, although I think the dealer still thinks he did the right thing. He said he's been using the mercon 5 for the last several years in the 4r100. I hope there hasn't been any damage. I'm going to try to get them to extend the warranty on the transmission. Thanks for all the replies.

 

mercon 5 will destroy a 4r100 transmission.

 

yeper. make sure they flush it out good

 

I was told by my dealer to use Mercon V. Three guys behind the counter said to go ahead and use V. I called another and he said NOT to use V and that in fact the XT-2-QDX is Mercon III. I am so confused. I also can NOT find straight MERCON and most of the fluids have multiple spec suchs as Mercon/Mercon V or Mercon/Mercon III.

 

There is no such thing as MERCON III. There is DEXRON III/MERCON, and that's what the 4R100 uses. DEXRON III and MERCON are just about identical, so one fluid meets both specs. Don't use MERCON V or any fluid that has both MERCON and MERCON V.

 

I found this link from an older post. It was very helpful. When I showed it to the dealer, he was speechless.
http://www.fcsdchemicalsandlubricant...ickref-atf.pdf

 

Sorry. typed in in wrong. http://www.fcsdchemicalsandlubricant...ickref/atf.pdf

 

Back in December of last year, I had my 30K service at the dealer. They did a complete flush and drain. They filled with 12 qts of MERCON V. I have put 22K since then and had ZERO issues. Until this tread, I never realized they used anything different than what they were supposed to.

 

After reading through this thread I checked what the dealer put in mine when they flushed the tranny. They filled it with the Mercon V as well. I only have about 3k on it since they did the flush and haven't noticed any issues either.
I've got an 01 V-10.

 

You are right, I messed up on the 'Dexron III' vs just 'Mercon III'. Just repeating what the parts department advised me.
oops

On the flip side with the PDF listed above, it clearly states,
"Use of a transmission fluid that indicates dual usage (MERCONŽ, MERCONŽ SP OR MERCONŽ V) in an automatic transmission application requiring MERCONŽ may cause transmission damage. Use of any fluid other then the recommended fluid may cause transmission damage."

Does this mean MERCON and DEXRON III designations as well since I guess it is a dual usage? I don't see anywhere in the PDF of any mention of Dexron III.

EDIT: I did a little research just now. I am not a mechanic which is why I did not know this but DEXRON III is a GM (chevrolet) specification whereas Mercon is the Ford spec. I couldn't find straight MERCON. I thought Dexron III/Mercon was a dual usage fluid for Ford. This is why I steered away due to the PDF listing of "Use of a transmission fluid that indicates dual usage (MERCONŽ, MERCONŽ SP OR MERCONŽ V) in an automatic ransmission application requiring MERCONŽ may cause transmission damage." where I read in this website elsewhere as well.

 

I had the dealer put the mercon (now called mercon 3) back into my transmission today. The part number on the mecon 3 quart was the same one listed on the PDF for regular mercon. It might be my imagination, but the shifts feel a little better (firmer) now than when I was running on mercon 5.