One or another of these transmissions are used in many vehicles including the Taurus, Sable, Windstar, and Continental. Geartrain meltdown due to an inadequate supply of pressurized lubricating oil is one of the primary causes of transmission failure in vehicles built prior to Independent transmission shops typically address the inherent design defect in the AXO, AXOD-E transmission by enlarging the orifice which feeds the lube oil and making sure that the bushings, which help control the oil flow, are replaced if the least bit worn. In mid, Ford redesigned the tubes above the oil filter and sent its dealers a service bulletin that attributed geartrain meltdown in all vehicles built in to a faulty gasket TSB A
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The Ford AX4S automatic transmission is a four-speed electronic overdrive transmission used in to Ford Windstar minivan. The transmission also has a bolt pan on the bottom, which is different from the bolt pan used on the newer AX4N transmission that replaced the AX4S in on the Windstar.
According to the Center for Auto Safety , the failure rate for these transmissions has been significantly higher than that for most other automatic transmissions. The AX4S transmission in my Windstar failed at 60, miles, the transmission in my Windstar failed at 86, miles.
I should also mention that I have also owned two Chrysler minivans, and the transmissions in both of those also failed at relatively low mileage. The high failure rate has been blamed on inadequate internal lubrication of critical parts, and a weak forward clutch piston that cracks and leaks pressure. Ford scrimped on the forward clutch piston, making it out of cast aluminum until , when they switched to a steel part due to all the trouble they were having with this transmission.
Ford has so much trouble with the earlier versions of this transmission that in it extended the warranty on Taurus transmissions to six years or 60, miles.
That's ancient history now, and the Windstar transmissions were only covered by the standard powertrain warranty. The operation of the planetary gearsets is controlled by four multiple-plate clutches, two band assemblies and two overrunning clutches. Hydraulic pressure is provided by a variable displacement pump driven by the torque converter.
The transaxle has a large chain drive on the driver side end under the cover with AXOD stamped on it. There is also a thermostatic fluid control valve inside the transmission that compensates for fluid expansion as the fluid gets hot.
When the fluid is cold, it routes more fluid to the main control body. As the fluid heats, up the valve slowly opens to allow some of the fluid to drain back to the sump. This helps keep the fluid level below the rotating parts of the transmission so it doesn't foam and become aerated which can cause erratic transmission performance. The transmission is controlled by the powertrain control module PCM , using inputs from the transmission sensors,vehicle speed sensor and other engine sensors.
Key components include:. For normal driving, leave the transmission in overdrive. This will prevent the torque converter from locking up or the transmission from going into 4th gear while driving. This increases available torque but also reduces fuel economy.
Some people call this the "sell or trade this vehicle now" light because it usually means the transmission is failing. The computer uses this information to control torque converter clutch lockup and internal transmission operating pressures. This signal is also used to control the torque converter clutch, gear shifting and internal pressure. The solenoids are located in the main control valve body, and are two-way, normally open solenoids. The PCM uses fluid temeprature to modify the shift characteristics of the transmission when it is cold.
The Electronic Pressure Control EPC Solenoid controls the hydraulic pressure inside the transmission by balancing the line pressure against the modulator pressure. The PCM has an adaptive strategy that allows it to modify the shift characteristics over time for smoother operation. If the battery is disconnected, these learned settings go away and the PCM has to start all over again, which may cause harsher shifts for several hundred miles until the PCM sorts things out again. Problems here can make the transmission feel jerky at low speed if the torque converter locks up too soon or fails to release soon enough, or cause a drop in fuel economy if the converter never locks up.
The PCM controls the upshifts and downshifts of the transmission based on vehicle speed, load and engine rpm. The transmission will downshift to a lower gear when the vehicle is slowing down, when an increase in the load on the transmission requires a higher gear ratio as when driving up a steep hill , or when the accelerator pedal is floored kickdown.
If the transmission downshifts harshly gong from 3rd to 2nd gear, or shudders when accelerating around a corner, the problem may be air in the transmission fluid caused by a low fluid level. Ford TSB covers this problem and says the fix is to check the fluid level after the vehicle has been driven, the fluid is hot, and the engine is idling in Park , and add fluid as necessary to bring the fluid level up to the full mark.
Always refer to your owner's manual or the marks on the dipstick for the type of fluid to use. Starting in , all Taurus and Sable vehicles require the newer Mercon V fluid. Ford warns that using wrong fluid or a fluid that does not meet their Mercon or Mercon V specifications can cause transmission problems and possible transmission failure. Transmission diagnosis is usually ot a job for a do-it-yourselfer.
It takes expertise and special equipment to properly diagnose a transmission problem. Here is Ford's recommended procedure: 1. Check the transmission fluid level. Many problems such as slipping, slow engagement and erratic or sloppy shifts can be caused by a low fluid level. If low, add the proper fluid to bring the level up to the full mark. Also inspect the transmission for leaks, and fix as needed to prevent fluid leaks. If the Check Engine Light is on, connect a scan tool to the vehicle diagnostic connector and check for any transmission-related fault codes.
If fault codes are present, refer to the appropriate Ford diagnostic charts and perform the required step-by-step checks to isolate the problem. If the transmission is still having a problem, connect a Ford Transmission Tester Rotunda and follow the appropriate tester instructions to determine if the problem is internal. Essentially, this involves checking internal transmission pressures and the operation of the various sensors and control solenoids.
An early symptom that your transmission is failing is a noticeable change in engine rpm of to rpm while driving at highways speeds in overdrive. Or, you may notice a flare in engine speed between gear shifts. This is often due to the transmission losing lockup pressure. If that is the case, sooner or later your transmission is going to call it quits and you will have to have it rebuilt or replaced.
Replacing a transmission on a Windstar or other front-wheel drive Ford is a difficult job, taking 8 to 12 hours depending on the skill level of the person doing the job, and how much trouble they run into with old, rusty fasteners. The engine has to be supported from above while the transmission and lower suspension components are unbolted and lowered to the ground. Another option would be to buy a low mileage used transmission from a wrecked vehicle in a salvage yard.
If you opt for used, make sure the transmission has been tested and comes with some kind of guarantee. The longer the guarantee, the better. My advice if you need a transmission rebuilt or replaced is to deal with a reputable transmission shop , independent repair garage or Ford dealer who will guarantee their work.
A quality rebuilt transmission should come with a warranty typically 1 to 3 years including labor. Below is a listing of the various Ford Windstar engine and transaxle combinations. You may need this information to correctly identify which transmission is in your Windstar. Ford TSB covers replacement of this piston with a stronger steel piston.
Key components include: The Transmission Control Switch TCS is on the end of the gearshift lever, and is used to turn overdrive on and off.
Turbine Shaft Speed Sensor.
Ford AX4S Transmission Problem
The AXOD transaxle has 17 bolts to retain its fluid pan. The electronic shifting and torque converter controls were integrated with the Taurus's electronic control module for smoother shifts. In addition to the name change, improvements in the lubrication of the gearset and capacity upgrades were made. A centrifugal piston assembly was implemented in the intermediate clutch position to improve 1st—2nd and 2nd—1st shift quality and an increase in the clutch's durability was made on some models. High energy friction materials were also introduced. The data plate code for this transmission is "L. Although similar in design and dimensions, it is a different transaxle than previous AXOD transmissions.
Ford AXOD transmission
In addition to the name change, improvements in the lubrication of the gearset and capacity upgrades were made. High energy friction materials were also introduced. Although similar in design and dimensions, it is a different transaxle than previous AXOD transmissions. The AX4N has 19 bolts to retain the fluid pan.
Remanufactured AX4N / AX4S Transmissions: Specs & Updates