1994 / WD21 : Automatic transmission fluid > Never changing

[jwblue]

The owner's manual for the 1994 says that the atf only needs to be changed if the vehicle is used for extensive towing.

Has anyone had a 1994 or WD21 that never had the transmission fluid changed?

How long did the transmission last and how did it run?

[Towncivilian]

As I said on NPORA: Not changing any lubricant is idiotic and neglectful. No lubricant can last the lifetime of a vehicle, only the lifetime of the manufacturer warranty which is their intent. Change it, there are no downsides. If it fails shortly after a change, it was going to fail anyway.

[jwblue]

I would love to hear from an engineer or technician from Nissan that developed this vehicle explain why atf changes are not necessary.

[Towncivilian]

Where does it say that ATF changes are not required? The factory service manual has a replacement interval of 30k miles.

[jwblue]

Where does it say that ATF changes are not required? The factory service manual has a replacement interval of 30k miles.

The manual only recommends when when the vehicle is used for towing or extreme driving conditions. It seems like it should always
be changed.

If towing a trailer, using a camper or a car-top carrier, or driving on rough or muddy roads, change (not just inspect) oil at every 30,000 miles (48,000 km)

[Towncivilian]

That suggestion is probably to lower apparent maintenance costs and downtime for the general public.

Somewhere around 75% of a transmission's total lifetime wear occurs within the first 5000 miles due to break-in wear and any crud left over from manufacturing (the latter point is becoming less of an issue for newer vehicles since manufacturing processes are always improving). If nothing else, an early change such as a full fluid exchange around 5k miles or at the very least a 30k mile simple drain and fill is arguably the most beneficial for a transmission (or any drivetrain component; differential, transfer case, even power steering) to evacuate break-in wear and prevent wear from compounding.

There is absolutely no reason not to change the fluid. The manufacturer is not always correct. The RE4R01A automatic transmission used in many WD21 Pathfinders was relatively weak to begin with at least when compared to the RE4R01A-HD model used in 2001+ Pathfinders and some other Nissan vehicles around those years. The RE4 in WD21s are known for failures resulting from debris and wear material clogging the cooler in the radiator (though in my opinion this is an unreasonable explanation) caused by lack of fluid changes. It is recommended to install an auxiliary cooler bypassing the stock cooler (or in-line with the stock cooler after thoroughly cleaning it out) as well as an in-line transmission filter to help prolong the life of the transmission.

[jwblue]

That suggestion is probably to lower apparent maintenance costs and downtime for the general public.

Somewhere around 75% of a transmission's total lifetime wear occurs within the first 5000 miles due to break-in wear and any crud left over from manufacturing (the latter point is becoming less of an issue for newer vehicles since manufacturing processes are always improving). If nothing else, an early change such as a full fluid exchange around 5k miles or at the very least a 30k mile simple drain and fill is arguably the most beneficial for a transmission (or any drivetrain component; differential, transfer case, even power steering) to evacuate break-in wear and prevent wear from compounding.

There is absolutely no reason not to change the fluid. The manufacturer is not always correct. The RE4R01A automatic transmission used in many WD21 Pathfinders was relatively weak to begin with at least when compared to the RE4R01A-HD model used in 2001+ Pathfinders and some other Nissan vehicles around those years. The RE4 in WD21s are known for failures resulting from debris and wear material clogging the cooler in the radiator (though in my opinion this is an unreasonable explanation) caused by lack of fluid changes. It is recommended to install an auxiliary cooler bypassing the stock cooler (or in-line with the stock cooler after thoroughly cleaning it out) as well as an in-line transmission filter to help prolong the life of the transmission.

My mother recently bought a 2012 Kia Soul.

I am going to recommend atf drain and fill every year. I think the investment will pay off.

[Towncivilian]

Go for it, just ensure the proper OEM fluid is used to maintain warranty should anything go wrong. Or better yet, have the dealer service it so everything is documented.

[Buzzman]

I know you probably don't want to hear this, but I have been driving for over 40 years (yes, I'm in my 60's now. The secret is out), and the few vehicles I've owned where I changed the transmission fluid....ALL had failures shortly after.
Prior to the changes, I had zero symptoms or problems with these vehicles. I didn't have a lot of miles on these vehicles either. In each situation, the fluid was changed because It was suggested that it was a good thing to do.
On the other side of the coin, on vehicles where I didn't replace the fluid...I've never had a breakdown or failure.
I've owned a lot of cars, and I tend to keep them a long time. I put a lot of miles on my cars before getting rid of them.
My Pathfinder now has 270,000 KMS. on it, and I have never replaced the transmission fluid....and I never will.
Call me crazy, but I'm not going to take the chance.

[jwblue]

I know you probably don't want to hear this, but I have been driving for over 40 years (yes, I'm in my 60's now. The secret is out), and the few vehicles I've owned where I changed the transmission fluid....ALL had failures shortly after.
Prior to the changes, I had zero symptoms or problems with these vehicles. I didn't have a lot of miles on these vehicles either. In each situation, the fluid was changed because It was suggested that it was a good thing to do.
On the other side of the coin, on vehicles where I didn't replace the fluid...I've never had a breakdown or failure.
I've owned a lot of cars, and I tend to keep them a long time. I put a lot of miles on my cars before getting rid of them.
My Pathfinder now has 270,000 KMS. on it, and I have never replaced the transmission fluid....and I never will.
Call me crazy, but I'm not going to take the chance.

Thanks Buzzman.

You are right. I didn't want to hear it. Now I don't know what to do.

Although, I have heard opposite stories. People did not change the atf, the transmission failed, and the person learned it
was due to dirty atf fluid. I am not sure how the person came to that conclusion though.

I guess I am going to have to do what makes sense which is to probably replace it every year.

After how many miles was the atf replaced on the vehicles? Was the transmission flushed or was the oil just drained and filled. It is my understanding that flushing can cause problems while just draining and filling will not.

[Towncivilian]

Most "horror stories" from transmission flushes are a result of owner neglect; the transmission starts exhibiting issues, and a "flush" is suggested as a last ditch effort before a rebuild or replacement. This is performed, but the transmission fails regardless a week later - the owner blames the fluid since it was the last thing done, not his previous neglect.

Also, transmission "flushes" described as forcing new fluid in at high pressure or even backwards simply do not exist. Flushes are simply another name for a full fluid exchange, and flush machines are simple bladders containing new and old fluid and adapters for connecting transmission cooler lines. However, some shops opt to add a flush additive, which is some harsh solvent which can cause issues. A complete fluid exchange with the correct fluid type and with the proper fluid amount checked properly after the service on a transmission that is exhibiting no issues should be completely harmless and absolutely beneficial.

[Buzzman]

Most "horror stories" from transmission flushes are a result of owner neglect; the transmission starts exhibiting issues, and a "flush" is suggested as a last ditch effort before a rebuild or replacement. This is performed, but the transmission fails regardless a week later - the owner blames the fluid since it was the last thing done, not his previous neglect.

Town, I totally understand what you are saying, and I don't doubt the validity of your comment.
I've experienced this problem with 3 different vehicles, 2 Fords and a Chrysler. None of them were high mileage vehicles, and none of them exhibited any prior transmission issues before I did the fluid changes.
Maybe it was just coincidence, and maybe the transmission's were due for failure regardless of what I did. I'll never know.
In the end, it comes down to personal choice I guess.
For me, it's three times bitten, fourth time shy.
FYI, this is not to say all maintenance procedures are bogus. For example, I never waver from regular oil changes (full synthetic), and other regular maintenance items. I'm just a little gun shy when it comes to transmission flushes.
Thanks.

[Towncivilian]

That is indeed why I said "most". I can't hope to explain your odd transmission failures. I hope yours were still under warranty or were rectified by the shop performing the service (if it was indeed a shop). I know some Chrysler vehicles transmissions, especially on some minivans, had finicky transmissions which could have explained that failure, but I don't know about the Fords.

In my personal experience, I'm pretty sure my Pathfinder had a full fluid exchange around 70k miles by some shop (if I recall correctly from my hazy memory of service records) and then a few drain & fills performed by myself, and a cooler line fluid exchange last Halloween and things are still fine. I also have an auxiliary cooler in-line with the stock cooler as well as a Magnefine in-line filter, and everything is still working fine at 139k miles.

[Buzzman]

It's the middle of winter here now, so I can't do a darn thing with my truck.
Very frustrating when I have some stuff I want to do to it. I have to be patient and wait until April or even May before I can jump back into it. It sucks.
I'm planning on doing the coolant this summer, as well as brake maintenance. I want to flush the brake fluid out. It's never been done.
I also have to do the power valve screws. Never been done either.
In the meantime, I'll do some thinking over the next few months and decide this spring if I'm going to do a drain and fill on the transmission.
Thanks for your feedback.

[Chris.m]

Just to further complicate things,

I changed my transmission fluid in March of 2011 with no symptoms (only hard 1-2 shift).

In April of 2011 my transmission went and needed to be rebuilt (Hard 1-2 shift is still there)

I don't want to say it is cause and effect, but it's one hell of a coincidence.

[Towncivilian]

Did you use Matic D fluid?

[jwblue]

Just to further complicate things,

I changed my transmission fluid in March of 2011 with no symptoms (only hard 1-2 shift).

In April of 2011 my transmission went and needed to be rebuilt (Hard 1-2 shift is still there)

I don't want to say it is cause and effect, but it's one hell of a coincidence.

Was that the first time?

Was it a flush or just a drain and fill?

How many miles?


Was the vehicle bought new?

[Chris.m]

Just to further complicate things,

I changed my transmission fluid in March of 2011 with no symptoms (only hard 1-2 shift).

In April of 2011 my transmission went and needed to be rebuilt (Hard 1-2 shift is still there)

I don't want to say it is cause and effect, but it's one hell of a coincidence.

Was that the first time?

Was it a flush or just a drain and fill?

How many miles?


Was the vehicle bought new?

Yes first time in my ownership.

Just a drain and fill

250,000km

I didn't buy it new.

[Chris.m]

Did you use Matic D fluid?

I don't really remember what fluid I used, but I had searched forums and service manuals, so I knew I had the right stuff.