Top Automatic Transmissions. The most reliable vs. most problematic automatic transmissions
This article contains the information about the most popular automatic transmissions. We will review the most common problems encountered in automatic transmissions, present the most reliable gearboxes and warn about troublesome transmission solutions. Moreover, descriptions of transmissions are supplemented by images and different videos containing some general information on transmissions and their components, typical problems and repair tips.
The most reliable automatic
transmissions
ZF 5HP 24/30
The mileage before the
overhaul is about 500,000 kilometers.
This family of 5-speed automatic transmissions has
been produced since 1992. There are several modifications of this transmission
range for cars with the longitudinal engine positioning. The modification
5НР30
was mainly used in 8 and 12-cylinder cars of BMW premium class. In addition, these
automatic transmissions were installed in such English cars as Aston Martin,
Bentley and Rolls-Royce. This transmission was designed for the torque of up to
560 Nm and had been produced before 2003.
In 1996 ZF released 5НР24 with the torque up to 440
Nm. This ZF transmission was installed in cars with front mounted longitudinal
engines such as Audi, BMW, Jaguar and Land Rover.
The modification 5НР24А was produced in 1997, intended
for all-wheel drive cars (AWD). This automatic transmissions was used in Audi
A6 and A8 (Quattro) and Volkswagen (4motion) cars. The torque capacity of this ZF
transmission is up to 430 Nm. All other automatic transmissions from the range
5НР24 / 30 were designed only for rear-wheel drive (RWD) cars.
The series of 5-speed automatic transmissions produced by ZF refutes arguments that a powerful engine drastically reduces the service life of the automatic transmission. In case with the 5НР series, especially modifications 24 and 30, high-quality ZF transmission parts often allow reaching the milestone of 500 000 km, even under intensive operational loads.
GM 5L40-E / 6L50
The mileage before the overhaul is about 400 000 – 450 000 km.
The 5-speed 5L40-E automatic transmission manufactured by GM was designed for engines with the capacity from 1,8 up to 3,6 liters and the maximum torque equal to 340 Nm. It had been produced from 1998 until 2007. Initially this automatic transmission was intended for cars with longitudinally positioned engine and the rear-wheel drive (RWD). This transmission was installed in BMW cars, namely, 323i and 328i models of e46 series. In 2000 GM released the modification for all-wheel drive (AWD) cars. The first BMW X5 models were equipped with this transmission. In 2001 GM engineers designed the version 5L50 which operated in harsh conditions on cars with the weight parameter equal up to 2300 kg and torque capacity up to 422 Nm. Moreover, since 2004 this automatic transmission has been used in less powerful rear-wheel drive (RWD) cars produced by GM: Cadillac CTS, Pontiac Solstice, Holden Commodore.
The 6-speed automatic transmission 6L50 was designed to replace 5L40. But it should be noticed, that these transmissions are almost the same when comparing reliability and durability parameters. 6L50 easily reaches the point of 400-500 thousand kilometers and can be distinguished by soft and smooth operation.
Chrysler 545RFE
The mileage before the
overhaul is about 400 000 km.
The 5-speed automatic transmission 545RFE was released
in 2001. This product became the next step in evolution of the 4-speed
automatic transmission
45RFE, produced since 1999. Initially 545RFE was
installed in Jeep Grand Cherokee WJ, and later in other cars of this brand such
as Jeep Grand Cherokee and Commander Wrangler. This automatic transmission was
also used in Dodge pick-ups (Dakota, Durango) and even in London taxi cars.
Chrysler called 545RFE as “multi-speed automatic".
Despite the fact that this transmission is used in cars subjected to high loads, car owners of cars equipped with this transmission rarely complain about any problems. This automatic transmission is a typical American transmission, which is notable for its slow gear shifting and a high operation resource. The repair of this transmission after 400 000 km is not complicated.
Toyota A340
The mileage before the
overhaul is about 700 000 km.
This 4-speed automatic transmission is designed for cars with the front engine positioning and RWD or AWD. Toyota has started manufacturing of A340 transmission model (named as AW30-40LE /-70LE according to Aisin classification) since 1986. This transmission is famous for its reliability and durability. To endure 300-400 thousand kilometers this automatic transmission may require replacement of worn-out friction clutches and seals. After some minor repair procedures the transmission may cover the same distance in miles. The first overhaul may be needed only after running 700,000 kilometers. This transmission was used for Toyota Runner, Supra, Lexus GS, LS etc. Under Aisin names such as AW30-40, 30-41, AW30-43LE / LS, AW31-41, AW31-81 this series of transmissions was successfully used for SUVs – Jeep, Montero, Terracan, Volvo, Lexus, Pajero, minibuses and small pickup trucks all over the world. New transmissions of this model are still manufactured in all non-Japanese assembly plants of Toyota (from Vietnam, Indonesia, the Philippines to Argentina and the USA). Competing with ZF and Mercedes for leadership on the market of automatic transmissions, Aisin designed its first 5-speed automatic transmission А350 in 1995 for rear-wheel drive (RWD) Lexus cars developed on the basis of A341E. But this transmission had been produced for a year and was replaced by A650 in 1997.
Toyota A750
The mileage before the
overhaul is about 600,000 km.
This 5-speed automatic transmission is mainly used in large SUVs and off-road Lexus and Toyota vehicles. Toyota has been producing this automatic transmission since 2003. A750 is not distinguished by its operational swiftness. But in terms of reliability it is one of the best transmissions, despite the fact that A750 constantly operates under heavy loads. For example, Toyota Land Cruiser equipped with this transmission in most cases operates in severe and extreme road conditions. It is hard to find a car with an A750 transmission, which would require repair before reaching 400,000 kilometers. Toyota transmission parts are quite durable and reliable. In Toyota A750 transmission only solenoids may exhaust their service resource quite early (during the first years), but this problem is easily solved by replacement of solenoids. Auto owners can rely on this transmission even after running several hundred thousand kilometers.
Mercedes 722.4
The mileage before the
overhaul is about 700,000 km.
Nowadays this automatic transmission is taken out of production. This Mercedes transmission is well-known for its exceptional durability. This 4-speed automatic transmission was produced since 1980s and was used in Mercedes 190-series, W124 and C-class cars. This transmission always operated with high reliability despite the engine type (4-, 5-, or 6-cylinder). The construction of 722.4 is almost “invincible”. Problems may occur in some particular Mercedes transmission parts, when the transmission is subject to severe operation conditions.
Jeep A904
The mileage before the
overhaul is 600,000 km.
This automatic transmission was released in 1960 and was used with 6-cylinder engines. This Jeep transmission is considered as a predecessor of all Chrysler transmissions. А904 is a modified version of the transmission designed in the 50s of the past century. This transmission was installed in Jeep Cherokee XJ, Wrangler YJ, TJ. Until now, many aftermarket manufacturers produce torque converters, shift kits for valve bodies, repair kits and friction clutches for this automatic transmission. Even American trucks with V8 engines were equipped with this transmission - that definitely testifies to the durability of A904. Due to a simple design, the Jeep transmission rebuilding is not very complicated and may be required after running 600,000 kilometers.
Mazda / Ford FN4A-EL / 4F27E
The mileage before the
overhaul is 500,000 kilometers.
This automatic transmission was designed thanks to combined efforts of engineers from Mazda and Ford. Both companies have different names for this transmission (Mazda-FN4A-EL/Ford-4F27E). Designed in 2000, this transmission has only 4-speeds and it is considered to be the only weakness of this product. The gear shifting is performed softly and smoothly, the torque converter can be locked within the wide range of revolutions per minute (RPM), which helps to reduce the fuel consumption. The main advantage of this automatic transmission is the fact that it rarely causes any problems. In rare cases does this automatic transmission require any repair procedures before reaching 500,000 km.
The most problematic
automatic transmissions
Aisin TF-80 SC
The cost of transmission repair
is about 1500$
.
The classic 6-speed automatic transmission is used in several dozen of car models, such as Opel, Ford, Fiat, Renault, Alfa Romeo, Volvo etc. Aisin engineers managed to design a compact transmission which has the same dimensions as a manual transmission. The construction of TF-80 SC is light and modern.
However, as time passes car owners of cars with this transmission may face some problems. In case of aggressive driving the torque converter activates the slippage mode leading to friction lining damage. The transmission filter, which can be structurally replaced during the transmission disassembly, also gets clogged. The oil, contaminated with dust, damages channels of the valve body that leads to pressure losses and wear-out of solenoids. Drivers often experience jerks when changing gears. The problem affects the 4-th, 5-th and 6-th gears. It is caused by improper functioning of solenoid-operated valves in the valve body. The neglect of this transmission problem may lead to its damage. In order to prolong the service life of this automatic transmission it is recommended to change ATF more frequently and to install additional fine filter. It is installed in the external line of the transmission cooling system.
Jatco JF011E
The cost of transmission
repair is about 2500$
In this continuously variable transmission (CVT) gear ratios change thanks to smooth change of the belt position on cone-shaped wheels. Theoretically, this type of transmission has many advantages. Almost an infinite number of gears allow keeping the engine in the optimal operating range depending on current needs of the driver. It helps to reduce the fuel consumption. The change of gear ratios is performed smoothly. Drivers who use Jatco JF011E never complained about any jolts or jerks that facilitates to a high level of comfort during driving.
Due to its design this CVT has small dimensions and light weight. This type of transmission is often criticized by drivers because of unnatural operation mode, which keeps the engine speed too high. During the operation, this CVT causes many problems for the driver.
The main element of CVT is a steel belt that wears out with cones. The repair may cost about 2500 dollars. In many cases the CVT control module gets out of order. To prolong the service life of this CVT it is not recommended using the car with CVT in harsh conditions: namely, high speeds, off-road driving, wheels slippage (in snow, mud). The fine filter should be replaced each 10-15 thousand kilometers.
Audi DL501
The cost of transmission repair
may reach up to 4000$.
The commercial name of this transmission is S-Tronic.
This automated transmission has two clutches (wet type) and is intended for car
models with the longitudinal engine arrangement with the maximum torque of 550
Nm and all-wheel drive (AWD) quattro.
DL501 has 7 gears and the range of gear
ratios may reach 8:1 depending on the engine.
Frequent problems with the mechatronics lead to the clutch package failure. Another issue, which occurs in this Audi transmission (also named as 0B5) more rarely, is related to the damage of the oil pressure sensor and shift fork sensors. The failure of abovementioned Audi transmission parts leads to the necessity of the whole ECU replacement, since the board and sensors are not produced separately. To make the matter worse, a new ECU can be only supplied in assembly with the mechatronics unit. It should be also taken into consideration that the ECU replacement requires deactivation of electronic components protection, which has been activated for all Audi models since 2008. This special protection can be deactivated only by an authorized Audi dealer, the procedure requires an online connection to the server in Ingolstadt. Owners of cars with this transmission often face different transmission issues. Not all repair services can provide high-quality repair for this transmission which is quite expensive.
ZF 6HP
The cost of transmission repair
may reach about 1500 $.
It is the 1-st 6-speed automatic transmission used for many car models. Firstly this transmission was used in BMW 7 produced in 2001. Nowadays ZF 6HP is installed in dozens of models. Basically, these are premium class cars or large SUVs. There are modifications of this transmission for all types of drive: front (FWD), rear (RWD) and all (AWD). ZF 6HP ensures fast and smooth gear shifting and practically does not increase the fuel consumption.
There are several versions of this transmission differing in size and torque capacity (up to 750 Nm) that allows using this transmission jointly with 6-liter engines. This feature is the main source of problems for this transmission. Such severe loads reduce the service life of any transmission. Almost all cars with ZF 6HP transmission are equipped with high-power engines. Moreover, engineers combined the ECU with the valve body, which resulted in frequent failures of the ECU. The ECU replacement costs about 1000 dollars. Problems also occur when the car transmission operates jointly with more powerful engines. ZF 6HP often has issues with the 4-th, 5-th and 6-th gears caused by the damage of the input shaft basket.
This transmission is very sensitive to the quality of the lubricant. It is recommended to perform the transmission oil change every 70 thousand kilometers. The oil change should also include replacement of the pan filter which costs more than 100 dollars.
LUK01J
The cost of transmission repair
may reach up to 5000$.
This continuously variable transmission (CVT) was
designed jointly by LUK and Audi and was named as CVT 0AN Multitronic or
VL-300. This transmission is intended for vehicles with longitudinally
positioned engine and front-wheel drive (FWD). LUK
01J has the torque capacity
up to 400 Nm. Engineers of this transmission used the chain instead of a steel
belt. Unfortunately, the majority of owners had a negative experience of using
this CVT. A typical issue with LUK 01J lies in jerks at low speed, even after
shifting to “N” mode, and blinking of driving modes indicators when shifting to
“D”. Car transmission problems occur after running 120-150 thousand kilometers
(and even earlier in case of aggressive driving style). The cost of repair may
reach up to 5 thousand dollars, which is economically irrational.
The most common cause of failure is the wear-out of the drivetrain and cone-shaped bevel gears. Drivers with this CVT should avoid towing because it has a negative impact on cones and breaks them. Frequently repair specialists have to deal with failures of the ECU, which controls the transmission operation. The multitronic is intended for the operational resource equal to 100 thousand kilometers. The whole unit operates in the oil which may heat up to 110° and higher. Thus, multitronic and its sensors often can not operate properly in such conditions. In addition, the multitronic may get damaged as a result of a small collision. To prolong the service life of this transmission it is recommended to add an additional radiator to the system, change ATF more often and thoroughly clean surfaces of the cooling system.
Aisin AW55-50
The cost of transmission repair
may reach up to 2000$.
This is one of the most common 5-speed automatic transmissions in production cars. This transmission was designed for front-wheel drive (FWD) cars with the engine capacity from 2 to 3 liters. This transmission was mainly installed in Opel, Volvo and Renault. However, AW 55-50 has constructive differences in various car models, so they are not interchangeable. One of the most typical drawbacks of this transmission lies in constant jerks when shifting from “N” to “D”, switching from 2-nd to the 3-rd gear and when taking off.
Fortunately, great popularity of this transmission, availability of Aisin transmission parts and a limited range of recurring problems allows transmission specialists to solve these problems. The reason of the most issues with shifting is the failure of solenoid valves (pressure line, torque converter clutch) of the valve body and wear-out of the valve body itself. Another problem is caused by leakages from the transmission radiator. The transmission oil should be changed every 30 thousand kilometers.
Jatco JF506
The cost of transmission repair is about 1500$.
This classic 5-speed automatic transmission is used in front-wheel drive (FWD) cars of many brands as an alternative to 55/50 produced by Aisin. Jatco JF506 distinguishes itself by its torque converter and by selection of gear ratios. In most cases malfunctions occur because of issues with the piston in one of friction packages. Another typical problem is the wear-out of solenoid-operated valves, which stop operating properly and should be replaced when reaching the mileage equal to 150 thousand kilometers. This problem is expressed in jerks when shifting gears. The pressure regulator failure is also considered to be a common problem, because this transmission component gets out of order earlier than other solenoids. This problem can be easily solved in the repair service. The matter is complicated by the fact that the transmission requires high-quality repair and turns out to be quite expensive due to the high price of spare parts. Otherwise, even inappropriate attitude to the oil change may lead to the transmission damage. The earlier the car owner goes to the repair service with JF506 transmission issues, the easier it will be to solve the problem.
GM6T35/40/45
The cost of transmission
repair is about 2000 dollars.
The family of 6-speed automatic transmissions,
produced by GM, is known under the name Hydra-Matic. The transmission is
designed for cars with the east-west engine mounting and the capacity from 1,4
up to 3.2. Different modifications of auto transmissions of this family have
different torque capacities.
The main problem in automatic transmissions produced
before 2010 was the drum 4-5-6 with damaged circlip, but later the design was
changed. The primary issue in Opel cars was the damage of the wave-shaped contact
spring. As a result, a large number of solid parts quickly damage the remaining
elements of the transmission. In this case the cost of repairs may reach up 2
thousand dollars.
Bushings also get significantly damaged because of
vibrations. Consequently, the oil starts leaking out and solenoids give more
pressure to compensate leaks. This leads to faster damage of bushings because
dirty and hot oil gets through the gaps of bushings.
Quite often car owners have to deal with the necessity
to replace the valve body and ECU with solenoids, damaged planetary gear set
and overheated pistons. The transmission was designed when GM had financial
problems, therefore this automatic transmission had a lot of shortages. But
starting 2010 it has been updated.
The list of recommendations on this GM transmission includes frequent oil changes, monitoring of the oil quality, installation of additional radiator, driving without reaching high torques and avoiding aggressive accelerations.
