Automatic transmission 4F27E: review, features, typical faults. Automatic transmission repair 4F27E (FN4A-EL)

Design and features of the box

The 4F27E automatic transmission is a hydromechanical transmission known for its reliability and unpretentiousness.
The developers decided to go further by using innovative electronic components in the gearbox control mechanisms: the degree of opening of the oil channels of the box is regulated by special solenoids, which made it possible to make the box smaller and lighter. Box solenoids layout:

In addition, such a technical solution made it possible to effectively cool and provide lubrication to the box components.

Inside the automatic transmission contains sensors:

temperature characteristics of the box coolant;
indicator of oil pressure in the system.

The latter is not typical for all gearboxes, but it is pressure sensors that make it possible to determine a malfunction of the oil system (oil leakage, etc.) in the early stages.

Another feature of the 4F27E box is fully electronic control. The gearbox selector is not directly connected to its units, due to which the possibility of failure of the gearbox mechanisms due to incorrect manipulations by the driver (for example, switching operating modes on the go, etc.) is almost completely eliminated.

Of course, one could reasonably argue that the abundance of electronics makes the box more complex, and each electronic node is an additional weak point. This statement is generally true, but the electronic components of the box were selected by engineers very carefully and are highly reliable. Failure of control elements is quite rare, and if the box has problems with the valve body or solenoids, this most likely indicates a mileage of over 300 thousand km, and not the best service. With proper service and oil changes, the service life of the 4F27E box is approximately equal to that of the car engine in which it is installed.

A major overhaul of the gearbox is usually carried out after the above-mentioned 300 thousand km. mileage, sometimes earlier, at about 200 thousand.

Code 4F27E contains an encrypted description of the box's features:

4 – indicates the number of transmission stages of the box;
F – means Front Wheel Drive, that is, automatic transmission for front-wheel drive cars;
27 – gearbox torque indicator. This figure encodes the figure 270 lb/ft, which means the maximum possible torque transmitted by the gearbox is up to 366 Nm;
E is the first letter of the word Electronic in the phrase Fully Electronic Control, which indicates the fully electronic control of the box.

Maintainability of the box A separate paragraph should highlight the maintainability of the box. 4F27E has a unique design, which makes it possible to overhaul it without removing the box from the car. This makes it easy to carry out all service and repair operations and, in addition, makes them significantly cheaper, since dismantling the automatic transmission in a car service is a separate service for an appropriate fee.

Where was the box installed? Various car models were equipped with the 4F27E gearbox over the years.

Ford:

Fiesta;
Festiva;
Laser;
Focus;
Ixion;
I-max;
Telstar;
Lynx;
Tierra.

Mazda:

Mazda 2;
5, 6;
Atenza;
Mazda 323;
Familia;
Demio;
MPV (VAN modification);
Biante;
Axela;
Tribute;
Protege;
Premacy;
Verisa.

Box design 4f27e

Automatic transmission 4F27E is a hydromechanical gearbox that is reliable and easy to maintain. Innovative microelectronic circuits in the device allow you to adjust the degree of opening of the oil channels, which are regulated by special solenoids, thanks to which it is possible to make a box with less weight and size. Technical features allow cooling and lubricating of box components.

Inside the automatic transmission 4f27e there are sensors:

To measure automatic transmission coolant temperature data.
Characteristics of oil pressure in the system.

The circuit includes fully auto-electronic control. The system selector does not have a direct connection with the units. This feature allows you to completely eliminate malfunction of devices due to illiterate actions of the vehicle driver. For example, when changing gears on the go.

Read

Basic malfunctions and repairs of Mazda 3 automatic transmission

Maintenance features of automatic transmission 4f27e

Major repairs to the 4F27E transmission are carried out when mileage exceeds 200-300 thousand km. Additionally, problems arise with the valve body and clutch basket. To repair or replace the valve body you will need a considerable amount of money, for this reason you need to comply with all the requirements and recommendations of the car manufacturer. This technique allows you to extend the service life of the 4f27e automatic transmission.

Checking the level and condition of the oil in the automatic transmission

Check the oil level using a dipstick. On new cars, the 4f27e gearbox requires an oil and filter change after 60 thousand km. It is recommended to use Mercon V type oil - 6.7-7.0 l. After 2003, frost-resistant DexronVI/Mercon LV began to be used.

Automatic transmission filter 4f27e is used depending on the modification and the depth of the pan. The most popular filtration products are produced with a 17 mm intake. The product has a simple non-woven membrane and is replaced with every oil change. Especially after the end of its service life.

Replacing transmission fluid in an automatic transmission

If you decide not to contact a car service center and change the transmission fluid yourself, you should carefully prepare. Drain the used liquid into a special container, you need to wait a certain time (about 15-20 minutes) so that the maximum amount of the old substance flows out.

Using this technique, it is not possible to remove all the oil; most of it remains in the torque converter, clutch drums and other components of the automatic device. Old transmission fluid contains burnt particles of the composition itself and other contaminants. To effectively change the oil fluid in an automatic transmission, you should resort to more complex types of maintenance.

Changing the oil in automatic transmission 4F27E

The cornerstone of routine maintenance necessary for long-term and high-quality operation of the gearbox is the replacement of transmission oil in it.

If you open the car manual (service book), you can find a record there about the transmission oil change interval of 40 thousand km. It is advisable to adhere to this instruction, although in practice in domestic realities the range of mileage after which the transmission fluid in the box is changed is from 30 to 60 thousand km. If the oil is changed on time, the transmission will last longer without major repairs, otherwise the unit is likely to fail, with further expensive repairs or replacement of the transmission with a contract one.

The 4F27E automatic transmission is filled with Mercon V type transmission fluid. In car modifications after 2003, the 4F27E automatic transmission oil was replaced with Dextron VI or Mercon LV - Low Viscosity. The latter option has a reduced viscosity (as indicated by the abbreviation LV), which allows the box to operate more easily at low temperatures, since the oil does not thicken. This is especially useful during a “cold start”, when the driver immediately starts driving in winter without warming up the automatic transmission.

For a complete change you will need about 7 liters of oil. For 4f27e, it is desirable to change the oil to “native” oil from the manufacturer; Mercon LV from Ford is available in the following cans:

For Mazda you should use ATF Mazda MV:

In addition to the fluid itself, to change the gearbox oil you will need a new filter. It consists of a non-woven membrane and must be replaced every time the gear oil is changed. There are several modifications of box filters, depending on the depth of the tray used:

with intake 17 mm;

with a high intake of 34 mm.

The latter is used in boxes found on Mazda cars.

Overhaul of the box

After reaching a mileage of 200-300 thousand km. The box may need major repairs. In its course, they usually use the so-called Overall Kit - a repair kit of gaskets and seals, which after such a mileage “get tired” and lose their properties. They also change bushings and clutches, for which there are their own repair kits.

In addition to the Overol Kit, there is also a MasterKit - a large repair kit for the 4F27E gearbox, which, in addition to gaskets and clutches, includes a set of steel discs.

If you do a complete overhaul of the box, a brake band is usually added to the repair kit. This is also done in cases where a car has been repaired with burnt-out clutches in the reverse or overdrive modes.

Automatic transmission repair 4f27e

Do-it-yourself overhaul of an automatic transmission is usually carried out after the mileage has crossed the 200-300 thousand km mark. During the work, the Overall Kit repair kit is used, which includes gaskets and seals. It is also necessary to replace bushings and clutches; for these, spare parts manufacturers produce special kits.

We produce the most complete kits for repairing automatic transmissions of the 4f27e brand, which include steel wheels. If the clutches of the reverse or overdrive modes are burned out, then a complete overhaul of the box is carried out; it is recommended to add a brake band to the repair kit. The work is carried out without disassembling the machine - the cover is a typical repair area.

Hydraulic unit

On the 4f27e automatic transmission, the valve body breaks down due to accumulated dirt and deposits collected on the pressure control valves, there are 7 of them. The valve system begins to jam as various particles enter it. There are times when the solenoid valve gets stuck in the open position.

All internal valves should be disassembled and polished, and the seats should be adjusted to fit them. If two people work, the job can be done in five hours. All spare parts are washed with R-5 solvent and carburetor cleaner.

Automatic transmission breakdowns and weaknesses:

1 . 3rd, 4th gear disappears - the direct clutch package is on. The reason is wear of the direct drum on the sealing rings, wear of the rear cover of the automatic transmission, loss of pressure along the direct piston, loss of pressure in the automatic transmission housing of the servo piston, wear of the cylindrical interface (can be treated by installing a bushing in the body). Consequence of operation with slipping 2-3: complete burnout of the direct package with the piston, drum, thrust ring and retainer. Then the reverse piston fails and reverse gear partially or completely disappears. 2 . Lack of 2nd and 4th gear. The reason is a break, burnout of the brake band or damage to the servo piston 2-4. 3 . No reverse gear only. The reason is the failure of the retaining ring holding the return spring of the piston, a defect in the reverse piston, the reverse clutch pack has burned out (crumbled), or the breakdown of the planetary gearbox (separation of the epicycle along the weld seam), this breakdown is relatively new and is found only on Mazda 6 and CX7 with more powerful 2.3 liter engines. 4 . The sudden appearance of a crunching sound from the automatic transmission, the car does not move - the planetary gearbox or differential has collapsed. Further operation if the differential breaks down leads to damage to the automatic transmission housing (the automatic transmission cannot be repaired). The cause of differential failure is the slipping of one wheel during dynamic starts and slipping in mud and snow, thermal sticking of the differential pin to the satellite; breaks the cotter pin that secures the pin in the differential housing. Under the influence of centrifugal forces, the finger comes out of the differential housing when moving and breaks the automatic transmission housing. If you're lucky and the pin doesn't fall out of the differential housing, it will simply saw through it. The chips get into the oil, damage the rubber seals, and then the clutches burn out. 5 . When checking the oil level in the automatic transmission, you found: pink foam like when cooking raspberry jam or drops of moisture, a rusty dipstick, all these signs indicate that antifreeze has entered the automatic transmission through the heat exchanger in the main radiator. Further operation of the vehicle will lead to burning of the clutch packs in the automatic transmission. During subsequent repairs of the automatic transmission, be sure to change all the clutches and locking in the torque converter, even if they look like new, as well as the radiator. 6 . Sometimes shift solenoids A and B fail. The automatic transmission goes into emergency mode P0750 P0755. The problem is solved by replacing the solenoids. 7 . Errors in the operation of the torque converter indicate shedding of the locking clutch or wear of the pump bushings. 8 . Shocks and shocks when switching from 2nd to 3rd gear, the reason may be wear of the housing and the servo rod of the 2-4 belt. It can be treated by installing a repair bushing into the automatic transmission housing. List of frequently replaced spare parts when repairing 4F27E FN4A-EL FNR5 FS5A-EL: a . Set of gasket seals; b . A set of steel and clutches (all or burnt and worn); V . A set of rubberized pistons and retainers (all or burnt and worn out) at least a direct and reverse piston; G . Servo piston (brake band drive); d . Reverse and direct drum (3rd-4th gear); e . Brake band 2-4 gear; e . Housing repair (installation of servo piston bushing); and . Rear cover (rolls out bushings and grooves for O-rings); z . Differential (the pinion axis flies out or the differential interface with the CV joint axle of the drive is worn out); And . Shift solenoids A B; To . EPC pressure regulator solenoid; l . Planetary gears (wear, breakdown); m . Filter; n . Electronic control unit for the automatic transmission TCM (errors in the unit or incorrect operation of the automatic transmission, which stops when the TCM >); O . Oil 8-9 liters Mercon V or compatible analogues; R . Remote radiator for cooling the automatic transmission (insufficient cooling, forever avoid the possibility of antifreeze getting into the automatic transmission); With . Engine mounts (shock when turning on D or R due to broken mounts);

4-speed Automatic transmission 4F27E Ford, Mazda. general review

The 4F27E 4-speed automatic transmission was designed in 1998. It has been on the production line since 2000.

4F27E was installed on cars:

MAZDA: 2, 3, 323, 5, 6, 8, ATENZA/5HB/WAGON, AXELA/WAGON, BIANTE, CX7, DEMIO, FAMILIA, FIGHTER, MPV (VAN), PROTEGE, TRIBUTE, VERISA.
FORD: ECOSPORT, FIESTA, FOCUS/C-MAX, i-MAX, LYNX, TELSTAR, TIERRA, TRANSIT CONNECT.

Design Features 4F27E

An interesting feature of the 4F27E box is its fully electronic control. The gearbox selector is not directly connected to its units, due to which the possibility of failure of the gearbox mechanisms due to incorrect actions by the driver is almost completely eliminated.

Also, the 4F27E automatic transmission has a unique design, which makes it possible to overhaul it without removing the box from the car. This makes it easy to carry out all service and repair operations and makes them significantly cheaper.

Basic faults 4F27E

Often the mileage is 150-200 thousand km. During traffic jams in megacities, the hydraulic unit fails. Symptoms: jerking/kicks when changing gears and shifting the gearbox selector.

The 4F27E valve body can be successfully repaired. After repair, the service life of the valve body is like a new one.

In the mechanical part, the planetary gear fails. Symptoms:

Noise when driving;
Complete refusal to move;
When switching from “P” or “N” to any speed, there is no noticeable push to engage any gear).

The 3rd-4th gear clutch is also destroyed. Symptoms: failure of 3-4 gears, darkening of the oil color.

The same thing happens with the reverse clutch. Symptoms: lack of reverse gear, incorrect activation with a delay, oil turns black. Damage to the differential is possible. Symptoms: noise when driving at speed, shocks occur when shifting gears, vibration when driving.

The rear cover of the automatic transmission also suffers from breakdowns. Wear of the seat on the cover caliper causes a drop in oil pressure. The reason for this is the development of sealing joints. Symptoms: 3-4 gears disappear, vibration is observed in the body when switching from 2 to 3 gear at idle.

This transmission has a low service life due to the oil seals, rubber-coated pistons and brake band. The locking clutch of the box is crumbling. The gearbox shift solenoids may fail and need to be replaced.

The average mileage before the first visit to a service station is 120-180 thousand kilometers. But there are also long-livers with 250-350 thousand kilometers.

The electrical part of the 4F27E automatic transmission is quite reliable.

Automatic transmission diagnostics 4F27E

Most questions about the causes of the malfunction can be answered immediately after the initial diagnosis. The transmission is easy to diagnose. An experienced craftsman can determine 90% of the upcoming repair work even from a conversation with a client. To do this, it is enough to obtain information from the client about the symptoms of the malfunction, how many times and how the oil was changed, what color of the oil and whether there are chips in the pan, how many owners the car had, whether additional cooling of the automatic transmission was installed, etc.

As part of the initial automatic transmission diagnostics, computer diagnostics are performed, an oil sample is taken, and the symptoms of malfunctions are analyzed.

The main results of the primary diagnosis:

— automatic transmission fault: yes/no;

— repair of the electrical part of the automatic transmission is required (braid, sensors, connectors): yes/no;

— only valve body repair is required: yes/no;

— repair of the hydraulic part (valve block, torque converter) and mechanical part is required: yes/no.

If there are problems with the mechanical part, then most likely there are problems with the valve body - wear products from the “mechanics” clog the solenoids and valves of the valve body.

To understand what exactly is broken in the mechanical part, you will need to remove, disassemble and defect the box. After the troubleshooting procedure, the list of spare parts to be replaced will be finally determined.

Automatic transmission repair 4F27E

Typical repair options for 4F27E:

The valve body is washed and repaired;
Clutches change;
Worn pump bushings are replaced with new ones;
The gearbox reverse drum can sometimes be restored, but more often a new one is simply installed;
A new piston is installed along with the drum;
The brake band is changed;
The differential or planetary mechanism of the box is changed after they fail;
The automatic transmission rear cover must be replaced.

Buying a used car with automatic transmission 4F27E.

Transmission repair is one of the most expensive types of repairs along with the engine, so when buying a used car you need to do diagnostics, both electronic and mechanical, take an oil sample, see if it is burnt, and conduct an intensive test drive in all modes : Traffic jam mode, Grandfather mode, Racer mode. If the oil is burnt, this means that the friction clutches are burnt. The smell of burning is a serious symptom that must be feared; if it already exists, it will only progress until repair of both the hydraulic and mechanical parts of the transmission.

Automatic transmission service 4F27E

An important factor in the long-term and uninterrupted operation of an automatic transmission is its maintenance. For this box we recommend:

Cleaning radiators (at least once every two years);
Installation of additional cooling;
Periodic diagnostics of automatic transmission.
Regular oil changes. The first two replacements should be made every 60 thousand km. mileage More frequent replacement is possible if desired. Subsequent replacements, due to the formation of increasingly large wear products, must be made every 40-45 thousand km. mileage and partial replacement method.

If you need to buy a used automatic transmission 4F27E

If there is more specific information on a specific instance of a used automatic transmission, including mileage and make/model of the car, then you can use a “used” one. If this information is unknown, how and what was exploited, then this option is a “pig in a poke.” When selecting a used automatic transmission, you need to select it in accordance with the serial numbers (transmission models), because there may be differences:

by fastening;
electronic control of the valve body;
gear ratio and number of teeth on the shafts/gears.

A discrepancy between the box model after installation will result in the appearance of an emergency mode, or a complete failure of movement, or the box will simply be technically impossible to install.

Tow truck.

If there are minor kicks in the 4F27E, then you can get to the service center on your own, but if there are already crunches, noises, gear failures, slipping, then you need to call a tow truck. Otherwise, the transmission will wear out catastrophically when operating under faulty conditions. This will lead to higher repair costs. It is better to use a tow truck to ultimately reduce the cost of repairs.

If you have any questions, write comments under this article, or call our specialist directly. The phone number is listed in the “Contacts” section. Also, through any messenger you can send the technician photos of spare parts, error codes, etc., or you can also call and consult on any issue.

The most common malfunctions of the 4F27E automatic transmission:

After several hundred thousand kilometers, these automatic transmissions almost always burn out the Direct and Overdrive Clutch packs, requiring replacement of gaskets, clutches, oil seals and bushings. In 2003, engineers tried to solve this problem by replacing Mazda clutches with reinforced one-way HeavyDuty designs, which partially solved the problem.

The weak point of the 4F27E automatic transmission is also considered to be the drum seat of the rear cover caliper, which leads to oil leakage from under the rings. This occurs due to transmission overloads during forced driving. Moreover, it has been noticed that the rear cover of the Mazda is much softer than the cover of the Ford, which leads to its rapid wear.

Typical faults 4F27E /FN4A-EL:

Reverse drum play on the stator of the rear cover

From the very first years of operation, the clutches of the Overdrive (No. 247100A) and Reverse packages began to quickly burn out.

And since 2003, on Mazda FN4A-EL they were replaced with reinforced one-way clutches Heavy Duty (No. 247100BE), after which the burnout of the OD package decreased, approaching in terms of service life the thin Reverse and Forward-Direct clutches. Sometimes they order a reinforced set of clutches and steel discs. #247100AK.

The second in turn to burn out is the adjacent Reverse package 247110 - 247130. This happens at the next stage of wear, when oil begins to leave the Reverse package.

The rapid combustion of these couplings is associated with the design features of this type of box. Many manufacturers have a similar problem, even the Japanese Aisin with the U140-240 .

In general, the combustion of eternal clutches occurs due to the fact that the seat of the drum 556 (right) on the support of the rear cover 759 wears out and oil leaves from under the Teflon rings. Low oil pressure - weak pressing - slipping - heating - combustion.

The problem is both structural (caliper cover) and computer settings, which allow the electronic accelerator to overload this weak transmission unit. Moreover, if in Ford this problem occurs on very old cars, then in Mazda old age creeps up very early.

And this forced driving leads to significant lateral loads on the caliper, transmitted from the differential by gear 712 through gear 710 - this distorts the drum 556 and the outer Teflon ring of the cover caliper 759 stops slipping and jams between the drum and the cover, rubbing the slot-groove, through which then There is a loss of oil pressure. First in the Overdrive package, and a little later in the Reverse package.

There are other problems in this package: chips and dirt trapped under the rubber piston seals, aging of overheated rubber, but these are secondary problems, “the problem of weakened immunity.”

Back cover FN4A-EL No. 247759

Experts say that the material of the FN4A-EL is softer than that of the Ford automatic transmission (4F27E), so problems with the rear cover usually do not arise on the same Ford automatic transmissions. The problem area of the Mazda FN4A-EL.

The cover is being restored.

If you continue to drive with these vibrations, the OverDrive Drum #247550 sitting on the cover caliper with the Reverse package #247556 (below) breaks, and then the brake band with Pistons - OverDrive (247960) and the servo piston. From a lack of pressure, first the clutches burn, and then the drums themselves.

Brake band Overdrive (2-4) No. 247020 can be considered a consumable; more details about this problem can be found in the predecessor CD4E . Its malfunction leads to problems switching gears 2 and 4.

There is a reinforced version of this band - Overdrive Brake Band (Heavy Duty 4F27E) - No. 247020-AH.