Putting the Wrong ATF in a Tranny

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So what could happen and what has been documented? Example - changing the fluid in a vehicle requiring Mercon 5 to something other than Mercon 5?

The reason I ask is because I bought a 2000 Mercury Sable for my daughter to drive back and forth to our local university. The ATF looked dirty, so I took it to my locally owned and operated oil change shop to have it flushed and refilled. I provided a new OEM transmission filter and they dropped the pan and replaced it as well as flushing out all the old ATF. I watched them do this - that's one of the reasons I like and trust this shop. I am not sure they used Mercon 5. The used the B&G machine and put a B&G additive.

Fast forward a year or so and about 10,000 miles and it's in the shop getting the tranny rebuilt. It has approximately 125,000 miles on it now. What's the chance the fluid had anything to do with it?
 
i guess we will find out in another 10k?

jk

How was it shifting before the first flush?

How was the progression of worsening shifting until it needing a rebuild now?
 
Certainly possible.. A flush probably had possibly more or at least as much to do with it. I have heard from a number of mechanics to never flush a transmission. Drain and refill only. Another factor is the fluid has you said
If the Sable is like my Nissan then using the wrong fluid is a big no no. OEM transmission fluid is a non negotiable aspect in car care to me. Motor oil can offer a little leeway within reason. But transmission fluid is not one to experiment with. Another factor to keep in mind too is that these transmissions are not known to be the strongest. That's why the big three collaborated to produce a better six speed transmission. My parents 99 Expedition transmission was replaced around the same mileage as the Sable here.. 130,000 miles. And that vehicle was babied and treated very well. Just a poor transmission in those vehicles too.
 
On a Honda, if you don't use the right stuff, and use, say Dexron III, and the Trans failed, I'd blame the fluid without question.

If they used the "wrong" fluid my guess is they used Dex III as their "universal" atf.

Read up what happened to others using Dex III in your trans would be a good place to start.

Personally I'd NEVER use any ATF other than Honda DW-1, they are that fussy.

But, your car may be less picky.
 
A/W sourced transmissions seem to do well on any atf, my Toyota doesn't seem to care what's in it.
 
Originally Posted By: Miller88
Those transmission (Ax4S, AX4N) were not that reliable. It died a natural death.


+1 to this many people had trouble getting to 100k in some cases.

I have a 99 Taurus with 145k short trip miles and it's still good. I never dropped the pan though, I only did suck and fills with a 50/50 mixture of Mobil 1 ATF and Mercon V.
 
I put mercon V in my Honda because the bottle said compatible wit z-1. Wrong! It caused immediate slipping. Put in castrol transmax import and Lucas no slip. About 99% better now. Definitely use oem fluid unless known substitutes will work but don't even trust a label on a substitute bottle.
 
Originally Posted By: bbhero
Certainly possible.. A flush probably had possibly more or at least as much to do with it. I have heard from a number of mechanics to never flush a transmission. Drain and refill only. Another factor is the fluid has you said
If the Sable is like my Nissan then using the wrong fluid is a big no no. OEM transmission fluid is a non negotiable aspect in car care to me. Motor oil can offer a little leeway within reason. But transmission fluid is not one to experiment with. Another factor to keep in mind too is that these transmissions are not known to be the strongest. That's why the big three collaborated to produce a better six speed transmission. My parents 99 Expedition transmission was replaced around the same mileage as the Sable here.. 130,000 miles. And that vehicle was babied and treated very well. Just a poor transmission in those vehicles too.


Come on, this is the old "A flush will kill your transmission" story which is not true. A flush is more of an automated fluid replacement. Always the pump in the transmission pushes around the fluid. The only job of the flush machine is to keep the pan filled with new ATF at the same rate the transmission's pump pushes it out.

Some places use a base ATF and add an additive to make it perfect for your vehicle. BG typically uses a cleaner before the flush and a conditioner after the flush. And the new fluid container in the machine probably has a QT of new ATF in it leftover which may or may not be the proper ATF for your vehicle.

Now a universal ATF by Amsoil should not be confused with a one size fits all. Its a one size fits many and another size fits some others. And so on.

Bottom line is the ATF should be spec'ed for your vehicle/transmission by a quality manufacturer.

Buying Amsoil for both my vehicles seems like an easy choice for me. But I will need to deal with CVT fluid at some point for the Subaru.
 
Originally Posted By: 901Memphis
Originally Posted By: Miller88
Those transmission (Ax4S, AX4N) were not that reliable. It died a natural death.


+1 to this many people had trouble getting to 100k in some cases.

I have a 99 Taurus with 145k short trip miles and it's still good. I never dropped the pan though, I only did suck and fills with a 50/50 mixture of Mobil 1 ATF and Mercon V.


What I would do with mine is pop the cooler line off - I added a large cooler - and use the trans pump to pump it down while filling it through the dipstick tube. Worked well.

Didn't stop the car from (literally) rusting in two at 75000 miles.
Did not stop the car from
 
Originally Posted By: 901Memphis
Originally Posted By: Miller88
Those transmission (Ax4S, AX4N) were not that reliable. It died a natural death.


+1 to this many people had trouble getting to 100k in some cases.


+2 for the above comment.
 
Only transmission I have experience with fluid wise is the Ford 4r70w. I've seen multiple vehicles that had torque converter 'shudder' with mercon 3 that were immediately cured with a change to mercon V.
 
Go ahead and flush every time.. A number of Nissan dealerships do not use the flush or pushing fluid method. In fact they do a drain and refill a couple of times over the course of a couple of weeks. Which is made easier with a drain plug on the transmission. There is a good reason why some of them do it this way. I have been told by a number of mechanics this is not the thing to do. A good friend of mine who runs his own shop for many years told me 2 ways to get a older car to stop working is either A. Use a strong fuel or injector cleaner on a gas tank that has nver had one used in it or B. Flush a older transmission. He has been working on cars for 25 plus years. Also I read on my local paper two mechanics with over 50 years experience did not like the flushing process in transmissions. But again.. Do want you want.. And you cannot argue that the big three transmissions were not the strongest during that time as well. That's why they worked together trying to fix those issues.
 
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Originally Posted By: nwjones18
Only transmission I have experience with fluid wise is the Ford 4r70w. I've seen multiple vehicles that had torque converter 'shudder' with mercon 3 that were immediately cured with a change to mercon V.


Extremely common with the transmission that would be in the Taurus; if the wrong fluid was used, it would have been shuddering pretty quickly.
 
Ford's automatic transmissions aren't the best, especially on that Taurus/Sable.

Besides, Mercon LV is backwards-compatible with V. Maxlife is great stuff.
 
Originally Posted By: Donald


Some places use a base ATF and add an additive to make it perfect for your vehicle. BG typically uses a cleaner before the flush and a conditioner after the flush. And the new fluid container in the machine probably has a QT of new ATF in it leftover which may or may not be the proper ATF for your vehicle.



Pretty sure this is what they did. Picked up the car today - $1,600 total for the rebuild with a rebuilt torque converter. Local shop where the owner did the work - one year warranty.
 
Originally Posted By: Miller88
Those transmission (Ax4S, AX4N) were not that reliable. It died a natural death.


I think this may well have been the case. 4th gear stopped working altogether and it was shifting so hard between 1st & 2nd and 2nd & 3rd I thought the tranny might fall out before I got it to the shop.
 
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