Mercon V, should I be worried?

[Bakes168]

I have a 2001 F250 7.3L with the 4R100 trans, around 245k miles on the truck. About a year ago I did a trans fluid flush following the write up by the retired Ford trans engineer who helped design the 4R100. I filled her with the Valvoline Dex/Merc fluid that was on sale at WM. I now learn that while Mercon was originally spec'd for this trans, Ford later changed the spec to Mercon V.

Should I be worried about driving with the current fluid in there? Should I perform another flush and fill with a Mercon V spec'd fluid?

She has the 6.0L trans cooler installed, average temps run around 120-140 F with normal driving and she doesn't tow much. At the moment she is driving and shifting well, no issues.

This is my first post on BITOG, I greatly enjoy learning from/with all of you fine folks!

 

[SZR48207]

I think you're fine, until your next -regularly scheduled- trans fluid change. Just use Mercon V then.

 

[28oz]

I agree. The Mercon V is a better fluid, but the Dex/Merc should meet the original spec. Just change it all at your next fluid change.

 

[buck91]

Wasn't the spec changed to Mercon V due to torque convert shuddering issues? I believe the work around is Lubeguard RED. That is, if you even develop any symptoms.

 

[double vanos]

First things first:

please have a seat and enjoy the ride..

 

[Langanobob]

That retired Ford transmission engineer is pretty active on Ford-trucks.com. For your peace of mind I suggest asking there and getting a reply from the horses mouth.

 

[69GTX]

I've read that there are additive packages (like Lubeguard green MV ATF supplement) that can enhance a Mercon towards Mercon V specs. Might be worth a try.

Lubeguard Faqs

My 2002 Lincoln calls for Mercon V. Note that my essentially identical 1997 Lincoln called for Mercon and that run to 232K miles flawlessly. I can't see the huge difference other than trying to get more life out of the transmission. On my last trans fluid change in the 2002 (42K miles to 71K miles) the info on the quick lube service said they did it with "Mercon." (Mercon or Mercon V?...and would they even care?). It wasn't until I got here at Bitog that I realized it wasn't right. If I could go back, I'd have changed out that "potential" Mercon fluid early at 15K-20K miles. The Mercon shears at probably twice the rate of the semi-synthetic Mercon V (from articles I've read), one good reason alone to use the Mercon V which has a 30K OCI on my vehicle. My car showed no negative issues with running Mercon for those 30K miles while running as smoothly as it always had. I'm now back on Mercon V. Advantages to Mercon V are it shears less, semi-synthetic at a minimum, and a better anti-wear/detergent add package than Mercon.

 

[SilverFusion2010]

Just use Mercon V next drain and fill. It replaced Mercon III in all applications but the older stuff will still do the job.

 

[Bakes168]

That's great news, thank you all for the info!

Now, I just wish WM sold Valvoline spec'd for Mercon V in gallon jugs like the Dex/Merc....

 

[28oz]

Originally Posted By: Bakes168
That's great news, thank you all for the info!

Now, I just wish WM sold Valvoline spec'd for Mercon V in gallon jugs like the Dex/Merc....


The Walmart Supertech Mercon V bottles are labeled as Ford approved/licensed. Should be as good as any other?

 

[Bakes168]

I don't think I saw any of the Supertech stuff last time, I may have overlooked it. They certainly didn't have any in gallon jugs like I want.