I have read online that there are thousands of complaints about 04 Ford Explorer 4.0 liter transmissions going out well before 100k.

Is this issue really this wide spread or did it only affect a small number of vehicles? Possibly lack of maintenance / wrong fluid, etc? I would doubt it would be to wrong fluid type since their isn't a dip stick for the average person to add fluid to.

How many miles on your factory transmission? I just bought a well maintained 04 explorer with 95k on the clock, trans shifts great, do I need to worry about it going out in the near future?

 

It is a dual problem, allow me to explain exactly what is happening.

There are design weaknesses. They are not the entire problem though, those faults need a trigger. Before I say what the trigger is, allow me to explain a little of where the automakers are coming from. The average consumer wants smooth shifts. They want the transition from one gear to the next to be as smooth and seamless as possible. In a typical automatic, this is achieved by allowing the clutches and bands to feather on and off, and apply gradually. This gradual engagement allows slipping to occur. Whenever these friction surfaces slip, several things occur. For starters, heat builds up on the surfaces. This heat can scorch the fluid that it comes in immediate contact with. Secondly, some of the fiction material wears off.

So there are two bad things happening here. The fluid starts breaking down. Burned fluid tends to be slightly acidic. There are buffers in the fluid that can counter the acids to a point. Newer spec fluids are more resistant to thermal breakdown, and have more detergents and buffers. But this is only part of the story. The second issue is the friction material. Some of these particles that wear off will settle to the bottom of the pan or get trapped by the filter, but there are lots of particles that are too small to be removed by the filter. In small concentrations, there particles are not harmful, there are ingredients in the fluid that can keep them in suspension and in a stable form. However, only so much can be held before the particles begin to settle out. There particles can settle in every part of the trans, not just the filter and pan. When these micro friction particles get in the valve bodies, solenoids, seals, etc., they act like a polishing compound. This wears on these parts, increasing the clearances. Once the seals, bores, etc. wear out enough, the pressure to engage the bands and clutches drops. Low pressure means more slipping occurs. More slipping means more heat and more friction material that gets lost. A self destructing cycle begins and the trans fails.

Regardless of the manufacturers recommended service interval, which is based on thermal resistance alone, the transmission should have the pan dropped and the filter replaced every 30,000 miles at the most. It does not need to be a complete fluid changeout, just get what drains out of the pan. If this is done often enough, there is no need to replace the residual fluid left in the torque converter and lines unless you are really picky about such things. This will remove much of the friction material in the fluid, and will replenish much of the buffers and additives. By dropping the pan, you can also spot early warning signs of a problem.

There is a fluid exchange procedure that can be used if you want to replace the remaining contaminated fluid. This does not need to be done on properly maintained transmissions, but it you have not dropped the pan in over 60,000 miles, it is a good idea. Basically, you drop the pan and change the filter, and refill with new fluid. Once that is complete, disconnect the return line at the trans cooler, and attach a piece of tube to the cooler, and route the other end to a 5 gallon bucket. Have an assistant cycle the engine on to allow fluid to pump out, then shut it off and add the same amount to the trans. Repeat until the old fluid is gone (you will see a color change). Some new fluid will be wasted. This method takes about 12 quarts, including the fluid you replaced in the pan.

There are valve body modifications that you can do to extend the life of the trans before it fails. Like everything, there are drawbacks to these mods, but they have benefits. The main benefits is less slipping, less heat, and longer transmission life. The drawbacks are that the shifts will be firmer and more noticeable.

Another thing that should never be done on these or any other transmission is a powered flush. Flush machines use pressurized pumps to exchange the fluid in the trans. These machines expose the trans to pressures it was never designed for, and very often use of such machines forgoes the critical dropping the pan and replacing the filter. I consider those critical steps. Commercial power flushes are more trouble than they are worth, and in my opinion and experience, cause a lot of problems, or accelerate existing problems.

 

And let's not forget that there WAS an incorrect fluid issue with several of these transmissions which Ford issued a recall for. The recall essentially had the shop install a fluid additive in transmissions which had not yet exhibited signs of failure. I have to wonder though if transmissions that originally left the factory with the incorrect fluid and had several thousand miles with no signs of shifting issues before the additive was added may still exhibit some residual effects over their life. The good news about this issue was it apparently only affected the shift solenoids which do not require a full rebuild of the transmission to replace.

-Rod

 

KhanTyranitar & shorod, very good info/advice. Thanks!

I am very **** when it comes to my vehicles maintenance. The first thing I do on an automatic trans vehicle is add a good aux trans cooler if it's not already there from the factory. I have NEVER flushed a transmission & I never would. I prefer dropping the pan and replacing what comes out. I have heard too many horror stories of trans failure after a flush and I wasn't about to take a chance at it.

The previous owner had the 30/60/90k services done at the Ford dealer. I understand that just because the dealer did these services doesn't mean they were done right, but I'll hope they were. It all comes down to which tech is working on your vehicle.

My vehicle was manufactured on 5/2004 any way to figure out if it was before or after the trans fluid screw up?

Thanks for the great advice, Rich

 

I bought a 2002 in 2003 with 25k miles. DRopped the pan and cleaned / changed filter/ changed the 5 quarts in the pan and reinstalled. Did again at 60k and 100k. Now has 145k and about time to do it again. Getting the crud out and adding some new oil with good addatives will help life. You dont need to do a flush or get all 13 quarts out.

 

With your build date, it was likely affected. Per Recall number 04B22, this issue impacts "All 2004 and certain 2005 model year vehicles equipped with 5R55S, 5R55E, or 5R44E transmissions and built between Job #1 2004 through September 22, 2004." The trick will be identifying how quickly the additive was added. Your dealership should be able to provide that information.

-Rod