When considering the proper ATF fluids per transmission, what would be a time frame before the transmission became symptomatic if the wrong fluid was used?

example: Your tran requires Mercon V. Dealer installs Mercon/Dexron III.

Would the vehicle have immediate symptoms? Or might it run for a long time and have a sudden breakdown? Are dysfunctions usually gradual?

another example: RP claims to exceed Mercon V chemistry additives, yet their label only reads Mercon/Dexron III. So, I sent off 4 oz. of virgin Motorcraft Mercon V straight from the dealer, 4 oz. of virgin Royal Purple ATF, Mobil 1 Mercon V, WalMart's brand of Mercon V and a few others.

The prominant chemicals detected which are found in most ATFs were near identical in most, except for Boron. Seems like this is the one that separates Mercon from Mercon V, yet I still cannot get an answer on exactly what the amount is to be in spec for Mercon V.

Motorcraft's Mercon V Boron level was 86. The next closest was Royal Purple with 64. Mobil 1 was in the 40s and so were the others. Yet, all claim to be Mercon V (meet or exceed). The Calcium, Phosphorus, and zinc were all fairly close.

No one's Boron level was as high as Motorcraft's and the universal average for Boron in Mercon V is 75. I sent of another sample of Mercon V (Motorcraft branded), from a different new bottle. This time the Boron level was in the 60s. (Quality control problem?) I would think the recipe would stay the same. Perhaps it only has to be in a range.

Regardless, of all the other ATFs I sent out, Royal Purple was the closest to the standard Motorcraft Mercon V, yet they do not advertise it, even as "exceeding" Mercon V specs.

We've used it for quite some time and have had no issues.

So, just how long will a transmission run smoothly before it becomes dysfunctional in either scenario? Can they go for tens of thousands of miles, then suddenly fry?

 

You went to all the trouble (expense?) to get samples of ATF analyzed? Wow.

So is this a "hypothetical" question or something that happened to you?

Older transmissions, like the E4OD and AOD were originally spec'ed for Merc III oil, but when Merc V became popular, Ford said that those trannys could safely run Merc V as well. So now the "wrong" fluid could be what they were originally designed to run on.

Newer ones in production like the 4r70w require Merc V because it has more/better friction modifier compounds than merc III.

My guess would be that the tranny would work fine for a while, maybe not at it's best performance but definetly drivable. The modifier compounds in the merc III fluid would get used up rapidly in a transmission designed for the better compounds in V. So after a couple thousand miles shifts would start getting hard, gears would take long to grab, and overdrive might crap out.

I doubt it would go bad all of a sudden, would be more of a slow destruction.

 

Nothing has happened to me. But it has occurred to my neighbor's brother....the first part anyway. Ultimately, as far as I've been told, nothing happened and his transmission is still fine.

As for the use of RP, that is currently what my truck and my brother's truck are running. No problems and drives like new.

As far as analysis, it was a shared expense among several, so my total cost was $22.50 plus shipping of $1.59. Not enough for me to dwell on. It's not any trouble to pour virgin oil in a container and mail it.

 

I had that very thing happen to a 99 several years back and yes it will harm the transmission. Merc V has friction modifiers that provide for quicker shifts with less slippage. Installing Merc III will make the transmission shift softer because there is more slippage. Eventually the friction material in the clutch packs will become impregnated (sooner rather than later) with the Merc III and the transmission will begin to slip. At that point it's to late to go back to Merc V. Change it now or add the correct amount of a suitable friction modifier. I would be raising holy hell with the dealer that made such a blunder. The correct fluid is written on the dipstick for cryin out loud.

 

The E4OD's were updated in 98 - all the seals, O-Rings and gaskets - Updated to handle the syntetic's. Back then , the oil harsher and more tame today to exspand the aplication.

I've always run Merc V in the past - Amsoil now - that's only because it stayes cooler than the 5 ever did..

I use to have an insert they put in the manual when I purchased the truck with this info - it on the web now..

 

He did. And your point is exactly what he told them. I'm not sure just how long he had the Mercon/Dexron III in there but it wasn't too long. The story told to me was that he went to the dealer, had his trans fluid changed, and went home. A week or so later he was organizing his maintenance receipts and noticed on the dealer paperwork that the order had written on it, "mercon" and not mercon V.

They redid it for him and if I recall the time frame was within a couple of weeks.

I was under the impression that when it comes to transmissions, if the wrong fluid is used, it doesn't take long (maybe even immediately) to notice a difference.

Thanks.

 

Doc, to answer your question with a broad brush stroke would be hard. Many variables. How many miles on the trans? What kind of maintenance and how often has it been performed? How one drives? Under loads? etc.......

Generally speaking, probably would notice problems after a few thousand miles. By that time, it's proabably too late just to change fluid.

Speaking of your Ody, I do know that lots of auto shops don't carry the spec'd fluid for Hondas and other foreign vehicles. When they replace fluid, they most likely put in DexIII stuff. Honda specifically states that you can run DexIII as a *temporary* fix. Many Honda owners have complained about trans problems after having someone other that the dealer drain trans fluid. Most likely the cause is improper fluid exchange. Most stated complaints with the transmission after a few thousand miles.

There is definetly something to it about using the fluid a make specs. The design for it is highly important.

Use fluid other than what is spec'd in the owners manual and you take your chances accordingly.

Personally, I've more real life experience with manual trans.

Regards,

Joey

 

I do not know the answers to all of these questions. The only other info that has been related to me is that his F150 has ~ 87K miles and he tows very often (a boat, and lawn care equipment). I do not know his maintenance schedule.

I will see if there's any other info he wants. Thanks very much.

 

The trans has gaskets, seals, clutch frictions and bands and need some lube qualities for the gear train.
The combination sets the fluid spec as determind by the designer.
Putting another fluid in won't do any harm in the short term but is not correct for the long term.
All other auto trans have the same things that need a desgn spec fluid that meets the requirements for the build that can even change over the years as different parts are used for upgrade.
Drain and flush the mistake and don't worry anymore about it.
As an example; I have a custiom built 4r70w that has different clutch and band material (non Ford) plus shift mods and hardend parts for toughness.
Aside from the same lube requirements, the only thing different is the friction material. The fluid used is pegged to the friction material and not the seals, gaskets or any other parts.
The fluid used now is Dextron III in a Ford trans that normally uses Merc V due to the non factory bebuild.
Your making more of this than needs to be.