Hi guys, I have a 05 F-150 that calls for Mercon V. I guess I’m missing something, because all I could find was Mercon-lll. I know Mercon V is backward compatible, but will I smoke this tranny putting the Merc-III in it? The reason I ask, is my trucks dipstick tube cracked off, and I found half of it with the dipstick laying on the motor mount. I put a new tube in, but nothing is showing on the dipstick(Checking while running)
I’ve already added a quart of Merc-III, and have two more. Should I stop now, and flush it all out, or continue adding the Merc-III?

 

You should only use Mercon V.

 

I know I should be using the Merc V, but if I use the Merc-III, is it going to damage it? Not really concerned about peak performance. The truth is that it’s an old truck, with lots of miles, and I really don’t want to do a whole flush right now.As stated, I just put a quart of Merc-III in it already.If it’s going to blow the tranny within a couple hundred miles or, less though, I guess I have too. What do you think?

 

Don't put any more in other than that 1 quart you already put in there. Finding Mercon V spec fluid is not that difficult. Walmart doesn't have it but Autozone, O'Reilly, and NAPA do, see links below.

https://www.autozone.com/motor-oil-a...art/811754_0_0

https://www.oreillyauto.com/detail/b...on+fluid&pos=9

https://www.napaonline.com/en/search...eftNav=leftNav

 

Thank you!

 

First, there has never been a MERCON III fluid. Show me a picture of what you have.

There was MERCON, and then MERCON V. MERCON was discontinued in 2006. MERCON V replaced it. Every auto parts store in the US has MERCON V. Every Wal-Mart has MERCON V.

MERCON will damage your transmission. Do not use it.

 

Mark, I searched Walmart's website before I posted. They do NOT list any Mercon V specific fluid. Lots of "universal" fluid, plenty of Dexron III, Dex/Merc, ATF+4, and CVT.

There is also Mercon SP, Mercon LV, and Mercon ULV. None of that is to be used to replace Mercon or Mercon V.

I think he may have put Dex/Merc in, that can be used for Mercon and Dexron III applications, but not Mercon V. One quart won't hurt it, but I wouldn't put more in.

 

Yep. Super Tech (Walmart's house brand) Mercon V is now gone from Walmart's website. I recall another thread about a year and a half ago where I noted it was getting harder to find in retail stores. Personally, I've moved on to the Valvoline multi-use.

 

Hmmmm...I just searched for MERCON V on Walmart's website and found Castrol, Valvoline, and Motorcraft MERCON V fluid. https://www.walmart.com/search/?quer...v&cat_id=91083

 

None of those are showing in stock at any of the 5 Walmarts here. It has to be ordered from walmart.com for shipment or store pickup. Easier to go to Autozone, O'Reilly, or NAPA.

 

Thank’s, you’re right, the bottle I have says Dex-III/Mercon. What I don’t understand is it’s tough to find? The first O’reiily’s I went to had nothing but the Dex-III/Mercon, So that’s what I bought. I went back to a different O’reiily’s today, and they only had three quarts of Merc V. They also don’t carry gallon containers. So I bought the three, and they said they would have more tomorrow. Same with Autozone,and Walmart. Autozone carries it, but was sold out in both the stores I visited. I’m thinking isn’t this the new stuff everyone needs? What’s with all the old stuff everywhere? Anyway, my apologies to everyone for my not reading the label properly, wasted all your guys time. Now my problem is, how do I get it all out? I also am very concerned about debris entering the open hole from the dipstick tube breaking off(Already replaced that).The truck has been started, put in forward, and reverse for approximately five feet. Should I just drop the pan, or pull the tranny and drain the torque converter? I even thought about having it flushed with a machine, but I’ve heard those are hard on the seals...Too much pressure, and I’m not sure the machine would get everything out anyway. I’m dead set on getting as much fresh Merc-V back in the tranny as possible, so I promise this will be my last request for advice. Thanks again to everyone!

 

One quart won't hurt anything. That's all you put in, right?

Mercon V is starting to be hard to find because since 2008, Ford has specified Mercon LV and Mercon ULV in new vehicles.

A machine is the best way to change fluid, as long as it's just used as a passive exchange machine, letting the transmission internal pump move the fluid, not the machine.

 

Yes, that’s all I put in. Thanks for the additional info. Really appreciate it.

 

No, this is the "old" stuff (relatively speaking) that was only in used for about a decade in production, only for specific Ford transmissions, and was discontinued in new vehicle production vehicles about a decade ago.

It went just a bit longer than that. Up through 2011 Rangers left the factory with Mercon V fills. Many of the transmissions had started switching over to the LV formulation for a couple of years prior.