AUTOMATIC & POWERSHIFT TRANSMISSION FLUID SPECIFICATIONS

Team News: 4.8 Transmission Fluids December 1, 1999 AUTOMATIC & POWERSHIFT TRANSMISSION FLUID SPECIFICATIONS DIFFERENTIATING OEM REQUIREMENTS Passenge...

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Transmission Fluids December 1, 1999

AUTOMATIC & POWERSHIFT TRANSMISSION FLUID SPECIFICATIONS DIFFERENTIATING OEM REQUIREMENTS Passenger cars, buses, large trucks, farm tractors, and construction equipment have different requirements for transmission fluids. This results in a plethora of OEM specifications: GM DEXRON , Ford MERCON , Chrysler ATF+3 , Allison Type C-4, Caterpillar TO-4, and so forth. As performance requirements change with changes in transmission design, the use of new friction materials, and the trend towards “fill-for-life” or “long-life” fluids, additional transmission fluid specifications are being issued. These include Chrysler ATF+4 and MERCON V. Since many of these fluids have unique requirements and are not interchangeable, this presents the potential for problems if the incorrect fluid is used in a specific transmission. In this article, we will discuss the different types of OEM fluids used in automatic and powershift transmissions, how they differ from each other, and which 76 product(s) should be used in each case. Although individual products have been discussed in previous Team News articles, this article includes more detailed information and incorporates the latest OEM specifications. Our goal is to help educate the consumer about the different products and hopefully eliminate misapplication of transmission fluids. Requirements of Automatic Transmission Fluids In general, ATF performance is defined by the service fill specifications of the manufacturers of passenger car and commercial vehicle transmissions. These specifications establish testing procedures and pass/fail criteria for performance parameters such as wear protection, oxidation stability, seal compatibility, and shift quality. The effect of the transmission fluid on the friction surfaces of the clutches and

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Transmission Fluids December 1, 1999

bands is of vital importance to smooth operation of the transmission. The transmission fluid must not attack the friction surfaces and must provide the correct frictional characteristics as the clutches and bands come into engagement in order to ensure acceptable driveability for a particular vehicle. These required frictional characteristics are defined by the transmission manufacturers and must not change significantly over the life of the fluid. Transmission fluids for passenger cars may be divided into two groups: those that contain friction modifiers, and those that do not. Friction modifiers are special additives that make the fluid more “slippery” under certain operating conditions. Until the mid-1970’s, Ford produced transmissions with relatively small frictional surfaces. The bands and clutches had to be applied quickly with high pressure to prevent overheating and wear caused by excessive slippage. This required a non-friction-modified fluid with a higher static coefficient of friction than dynamic coefficient of friction. That is, the frictional forces between the clutches and bands are greater when there is no relative motion between the components (lockup) than when they are sliding against one another before lockup (see Figure 1). This produces a characteristic “hard” shift.

Figure 1. Ford Type F Frictional Requirements (High Static Friction). GM transmissions, on the other hand, require a more “slippery” fluid to permit smooth shifting without shudder. As the clutch or band locks up, friction modifiers react to actually decrease the coefficient of static friction. That is, the coefficient of static friction is less than the coefficient of dynamic friction (see Figure 2). This allows the use of lower clutch and band application pressures, resulting in a very smooth shift feel, but requires larger bands and more plates in the clutch packs to prevent excessive slippage and heat buildup.

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Figure 2. GM DEXRON Frictional Requirements (Low Static Friction). Use of the wrong fluid in either transmission could result in poor shift quality and shortened component life. Use of a GM DEXRON fluid in any 1961-1976 and some 1977-1981 Ford transmissions would lead to excessive slippage and rapid wear of band and clutch friction material. Conversely, use of a Ford Type F fluid in a GM vehicle would induce stiff shifting and customer complaints. Today, there are only minor differences in the frictional requirements for Ford and GM transmissions, so that one fluid can be used for both. But other manufacturers, such as Chrysler and Toyota, have different frictional requirements for their transmission fluids. Thus, the customer must be aware not only of each manufacturer’s fluid requirements, but also of the model year of the vehicle. Differences in frictional characteristics are the primary reason why one transmission fluid cannot be used in all transmissions. Requirements of Commercial Transmission Fluids The fluid requirements for automatic and semi-automatic transmissions used in larger commercial vehicles are defined by manufacturers such as Allison (Type C-4) and Caterpillar (TO-2, TO-4). The frictional requirements for Type C-4 and TO-2 fluids are very broad. Both specifications can be met with friction-modified passenger car ATFs and tractor hydraulic fluids, or with non-friction-modified heavy-duty engine oils and Caterpillar TO-4 fluids. On the other hand, the newer Caterpillar TO-4 specification calls for a fluid with substantially different frictional characteristics (more like a Type F fluid), improved wear protection, and enhanced seal and friction material compatibility. The demanding Caterpillar TO-4 specification defines a fluid that is essentially a unique, specialty lubricant.

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Powershift transmissions used in off-highway construction equipment have different fluid requirements than passenger car automatic transmissions because of higher load factors and the use of a wider variety of clutch materials. Current passenger car ATFs are friction-modified for smooth shifting, whereas commercial powershift fluids are not friction-modified in order to obtain the highest clutch and braking capacity. Powershift transmissions require more active antiwear and EP protection than passenger car transmissions because gears and bearings are much more heavily loaded. Passenger car ATFs use a viscosity modifier to give good low temperature performance, whereas OEMs such as Caterpillar and Komatsu prefer monograde oils (i.e., no viscosity modifier) that are not susceptible to shear so that the gears obtain maximum oil film thickness. European OEMs such as Voith and ZF also have a high shear stability requirement for transmission fluids used in their commercial transmissions to assure adequate film thickness. Powershift transmissions use a wide variety of clutch materials, such as paper, elastomeric, bronze, and graphite, whereas passenger car transmissions use mostly paper friction materials. In addition, certain off-highway equipment and all farm tractors utilize oil-cooled brakes, so wet brake friction performance is important. These differences are summarized in Table 1. Passenger Car ATF

Powershift Fluid/TO-4 Fluid

Friction-modified for smooth shifting (“slippery”)

Not friction-modified for highest clutch and braking capacity (“grabby”)

Less active AW and EP for lighter loads

More active AW and EP for heavier loads

Viscosity modifier for low temperature performance

No viscosity modifier for maximum film thickness (shear stability)

Mostly paper friction materials; no wet brakes

Paper, elastomeric, bronze, and graphite clutch materials; wet brakes

Table 1. Differences Between Passenger Car ATFs and Powershift Fluids. In the following sections, we will discuss the different passenger car and commercial transmission fluid specifications and list the recommended 76 product(s) for each.

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PASSENGER CAR AUTOMATIC TRANSMISSION FLUIDS Ford Motor Company For 1960 and earlier model-year automatic transmissions, Ford recommends the use of a Type A or Type A, Suffix A fluid. These fluids are first generation friction-modified ATFs developed by General Motors. 76 Multi-Purpose ATF or 76 Super ATF may be used in these vehicles. For Ford automatics in 1961-1976 model-year vehicles, and in many 1977-1981 models, Ford ESP-M2C33F (Type F) fluid is required. Many early 1980’s Mazda, Toyota, and Volvo automatics also specify a Type F fluid. This fluid is not friction-modified. 76 ATF-Type F is specially designed for use in these transmissions. If 76 ATF-Type F is not available, 76 HT/4 Fluid 10W may be used as an alternative. Do not use a friction-modified fluid such as 76 Super ATF, 76 Multi-Purpose ATF, or 76 ATF+3  Fluid in these transmissions; this could result in poor shift quality and accelerated wear from excessive slippage, as discussed above. (Note: The Ford ESP-M2C33G specification is a non-friction-modified fluid for certain Ford transmissions made in Europe. 76 ATF-Type F may be used in those transmissions.) In 1977, Ford’s first friction-modified transmission fluid, ESP-M2C138-CJ (Type CJ), was introduced. This was followed in 1981 with an improved fluid with better friction characteristics, ESP-M2C166-H (Type H) fluid. 76 Super ATF or 76 Multi-Purpose ATF are recommended for transmissions specifying Type CJ or Type H fluids. Starting with 1988 model-year vehicles, Ford began using the MERCON  specification (Ford ESP-M2C185-A) for all its worldwide requirements. This fluid was developed to reduce the number of ATFs needed to service Ford automatic transmissions, and is also used in certain Jeep/Eagle and Mazda automatics. It has frictional characteristics very similar to GM DEXRON fluids. The MERCON specification was revised in 1992, with significant improvements in oxidation stability, friction retention, wear protection, and low temperature properties. MERCON fluids are back serviceable to all Ford vehicles produced since 1981, and some earlier models, and replace DEXRON -II, Type CJ, and Type H fluids in Ford’s recommendations. MERCON fluids specifically do not replace Type F or Type G (European) fluids, because those fluids are not friction-modified.

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76 Super ATF is recommended for use in all Ford transmissions specifying MERCON fluid (but not MERCON V fluid, as discussed below). For pre-1992 vehicles specifying MERCON fluid, 76 Multi-Purpose ATF may also be used. (Note: 76 Multi-Purpose ATF does not meet the low temperature viscosity requirements of the revised MERCON specification, and hence is not recommended for newer vehicles.) For certain 1997 and later vehicles, Ford specifies MERCON V fluid. MERCON V was developed primarily as a factory fill fluid for transmissions with continuous slip torque converters. It is intended as a “fill-for-life” fluid under normal driving conditions, with a 30,000-mile drain interval under severe conditions. ( Note: Severe conditions are defined as towing a trailer or camper; extensive idling or low speed driving; operating in dusty conditions; and off-road operation.) The MERCON V specification calls for significant improvements in anti-shudder durability, shear stability, low temperature fluidity, and antiwear performance. MERCON V is back serviceable for most Ford automatics except those specifying Type F fluid. MERCON V ATF has significantly different physical properties than current DEXRON -III/MERCON fluids such as 76 Super ATF. Low temperature viscosity targets are 5,000 to 13,000 cP at –40oC, compared with a 20,000 cP limit for DEXRON -III/MERCON fluids. This lower limit can only be met with synthetic, part synthetic, or highly refined high VI, wax-free mineral base oils. 76 Lubricants Company currently does not offer a MERCON V product, but will be adding a MERCON V fluid to the product line next year (2000). Fluids meeting MERCON or MERCON V requirements must be licensed to use the MERCON trademark. Approved fluids are assigned a unique identification number (M-xxxxxx). Only fluids meeting the latest MERCON or MERCON V specifications may be licensed. A summary of the recommended 76 products for Ford automatic transmissions is given in Table 2. For additional history on Ford Motor Company ATFs (through MERCON ), please review Team News 4.4.

Team News: 4.8

Model Year

7

Specification

1949-1960

Transmission Fluids December 1, 1999

Name

76 Product

Type A or Type A, Suffix A

Super ATF Multi-Purpose ATF ATF-Type F HT/4 Fluid 10W Super ATF Multi-Purpose ATF Super ATF Multi-Purpose ATF Super ATF Multi-Purpose ATF

1961-1981

M2C33-D/F

Type F

1977-1981

M2C138-CJ

Type CJ

1982-1987

M2C166-H

Type H

1988-1992

M2C185-A

MERCON

1992-present

MERCON (revised)

1997-present

MERCON V

Super ATF Product to be introduced in 2000

Table 2. Ford Motor Company Passenger Car Automatic Transmission Fluids. General Motors Corporation For 1966 and earlier model-year vehicles, GM recommended the use of either Type A or Type A, Suffix A fluid in its automatic transmissions. Starting with 1967 model-year vehicles, GM began specifying DEXRON fluid (GM 6032-M). Type A and DEXRON fluids are friction-modified. DEXRON has undergone several upgrades through the years, with improvements in low temperature fluidity, high temperature oxidation stability, retention of frictional properties in service, and seal compatibility. These improvements, plus improvements in transmission design, have resulted in increased drain intervals. Current DEXRON  -III fluids are fill-for-life under normal service, with a 50,000-mile drain interval for severe service (for most vehicle models). DEXRON -III quality is used as a model fluid by many other manufacturers, including certain European and Japanese OEMs. DEXRON -III fluids (GM 6297-M) are back serviceable to 1949 for all General Motors automatic transmissions used in passenger cars and light trucks. DEXRON  -II fluids (GM 6137-M) cannot be used in 1992 and newer vehicles because they do not meet the low temperature viscosity requirements of the DEXRON -III specification. Thus, 76 Super ATF may be used in all GM transmissions specifying DEXRON (or Type A) fluid, while 76 Multi-Purpose ATF is recommended only for use in pre-1992 vehicles.

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As with MERCON fluids, DEXRON fluids must be licensed to display the DEXRON trademark. Only DEXRON  -III fluids may be licensed; all previous DEXRON and DEXRON -II licenses are obsolete. Approved fluids are issued a unique identification number (G-xxxxx). GM has announced plans to upgrade their DEXRON  -III specification, possibly to DEXRON -IV, but the exact timing is uncertain. Details of this new specification will be discussed when they are released. A summary of the recommended 76 products for GM automatic transmissions is given in Table 3. For additional historical information on GM ATFs, please review Team News 4.4. Model Year

Specification

1949-1966

Name

76 Product

Type A or Type A, Suffix A

Super ATF Multi-Purpose ATF Super ATF Multi-Purpose ATF Super ATF Multi-Purpose ATF

1967-1973

GM 6032-M

DEXRON

1974-1991

GM 6137-M

DEXRON -II/IID

1992-1994

GM 6137-M

DEXRON -IIE

Super ATF

1995-present

GM 6297-M

DEXRON -III

Super ATF

Table 3. General Motors Passenger Car Automatic Transmission Fluids. Chrysler Motors For all 1987 and earlier model-year vehicles, Chrysler recommends the use of a DEXRON -IID quality fluid in its automatic transmissions. For 1988 and later vehicles, Chrysler specifies a special MOPAR ATF-Plus (Type 7176) fluid. Hyundai and Mitsubishi also recommend the use of ATF-Plus fluids in their automatic transmissions. This fluid was developed to eliminate shudder upon lockup or partial lockup in automatic transmissions with lockup torque converters. It has different frictional characteristics than DEXRON /MERCON fluids, allowing a bit more slippage.

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MOPAR ATF-Plus has undergone several upgrades through the years, with current ATF+3 quality fluids having a recommended 30,000-mile drain interval under normal service. 76 ATF+3 Fluid is specially formulated for use in transmissions that specify MOPAR ATF+3 , ATF+2 , or ATF-Plus , and is the only 76 product recommended for those transmissions. If 76 ATF+3  Fluid is not available, 76 Super ATF may be used for topping off only, but not for complete fill since this may affect shift quality. Chrysler requires written approval to use the ATF+3  trademark, but it does not have a formal licensing program at this time. For 1999 model-year front-wheel drive vehicles, the factory fill fluid is MOPAR ATF+4 (Type 9602), which is intended to be a “fill-for-life” fluid. Currently, MOPAR is the only marketer of ATF+4 . No formal service fill program has been announced to date, and hence there are no commercial products available as of yet. Interestingly, the specification for ATF+4 not only has specific performance criteria requirements, but also specifies the additive chemistry and the particular basestocks that may be used! A summary of the recommended 76 products for Chrysler automatic transmissions is given in Table 4. Model Year

Specification

Name

76 Product

DEXRON -IID

Super ATF Multi-Purpose ATF

MS-7176B/D

ATF-Plus , ATF+2

ATF+3 Fluid

MS-7176E

ATF+3

ATF+3 Fluid

MS-9602

ATF+4

No product

Pre-1988 1988-1997 1998-present 1999-

Table 4. Chrysler Motors Passenger Car Automatic Transmission Fluids. Import Vehicles Most import car manufacturers accept DEXRON -II, DEXRON -III, or Type 7176 fluids for service fill in their automatic transmissions. Mercedes-Benz accepts only MB approved fluids, while Sterling and Toyota (Lexus) recommend only their own branded

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ATF. Some general fluid recommendations for import cars are listed in Table 5. These recommendations do not necessarily include all vehicle models, so always refer to the owner’s manual for the proper fluid recommendation. ( Note: Listing of 76 products here does not signify formal OEM approval. For approvals outside the United States, some European and Japanese OEMs require comprehensive in-house testing in addition to the latest DEXRON approval.) OEM Acura Audi BMW Daihatsu Honda Hyundai Infiniti/Nissan Isuzu Jaguar Lexus Mazda Mercedes-Benz Mitsubishi Peugeot Porsche Saab Sterling Subaru Suzuki Toyota Volkswagen Volvo

Model Year

Recommended Fluid

76 Product

Pre-1996 Pre-1995 (most) Pre-1996 (most) Most models Pre-1996 Pre-1996

DEXRON -II DEXRON -II DEXRON -III DEXRON -III DEXRON -II Type 7176 DEXRON -II (under warranty) DEXRON -III (out of warranty) DEXRON -III DEXRON -III Type F Toyota Type T IV DEXRON -II OEM approved fluid Type 7176

Multi-Purpose ATF Multi-Purpose ATF Super ATF Super ATF Multi-Purpose ATF ATF+3 Fluid

Most models Most models Pre-1997 Borg-Warner Most models Most models All models Pre-1997 (most) Most models Most models 4-speed 3-speed All models Most models Most models Pre-1984 (most)

DEXRON -II DEXRON -III DEXRON -III Type F OEM branded fluid DEXRON -III DEXRON -III Type F

Post-1983 (most) Pre-1996 (most) Pre-1984 (most) Post-1983 (most)

DEXRON -III DEXRON -II Type F DEXRON -III

Multi-Purpose ATF Super ATF Super ATF Super ATF ATF-Type F no product Multi-Purpose ATF Super ATF * ATF+3 Fluid Multipurpose ATF Super ATF Super ATF ATF-Type F no product Super ATF Super ATF ATF-Type F Super ATF Multi-Purpose ATF ATF-Type F Super ATF

*Note: Meets OEM requirements, but MB is not granting new approvals at this time.

Table 5. Import Passenger Car Automatic Transmission Fluid Recommendations.

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Passenger Car Manual Transmission Fluids Although domestic and some European automakers recommend ATF (DEXRON  -III or MERCON ) for use in some of their manual transmissions, the more common recommendation is either an SAE 75W-90 API GL-4 or API GL-5 gear lubricant or a genuine OEM gear lubricant. These fluids will not be discussed in this article. COMMERCIAL AUTOMATIC & POWERSHIFT TRANSMISSIONS Allison Automatic Transmissions The Allison Division of General Motors offers both fully automatic and semi-automatic transmissions for trucks, buses, and off-highway equipment. The earliest fluid specification, Type C-1, called for a high quality SAE 10W heavy-duty engine oil. In 1967, the Type C-2 specification was issued and included a transmission oxidation test and a power steering pump wear test. This specification was succeeded by Type C-3, which included a test for retention of frictional properties and covered both SAE 10W and SAE 30 viscosity grades. Engine oils, DEXRON /DEXRON -II fluids, and specialty fluids met the requirements of these specifications. The current specification for GM Allison automatic and powershift transmissions is Type C-4. This specification has more severe oxidation stability requirements than Type C-3 fluids. Type C-3 fluids are no longer recommended for use in Allison transmissions. There are many types of fluids that meet the Allison C-4 specification: heavy-duty diesel engine oils such as 76 Triton QLT, 76 Guardol QLT, 76 T5X Heavy Duty, and 76 Firebird HD; tractor hydraulic fluids such as 76 Hydraulic/Tractor Fluid and 76 Firebird Tractor Hydraulic Fluid; Caterpillar TO-4 fluids such as 76 HT/4 Fluid; and passenger car ATFs such as 76 Super ATF and 76 Multi-Purpose ATF. Allison issues a C-4 approval number for qualified products and publishes a list of approved fluids. The fluid recommendations and drain intervals for GM Allison transmissions were discussed in Team News 4.7. In review, the preferred fluid for on-highway transmissions is a Dexron -III fluid, i.e., 76 Super ATF. The preferred fluid for off-highway transmissions is a C-4 qualified heavy-duty diesel engine oil, i.e., 76 Guardol QLT 10W, 15W-40, or 30, depending on ambient temperatures.

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Caterpillar Powershift Transmissions From the early 1970’s until 1991, Caterpillar recommended API CD engine oils that meet the requirements of Caterpillar’s TO-2 friction test and a fluoroelastomer seal test for use in their transmissions and final drives. The TO-2 friction test measures the friction retention of oils used in oil-cooled clutches containing bronze friction materials. This same standardized test was also one of the requirements for MIL-L-2104D qualification of engine oils. DEXRON -II quality ATFs and multipurpose tractor hydraulic fluids also meet the requirements of TO-2. In 1991, Caterpillar issued a new specification, TO-4, with significantly enhanced performance requirements for their newer equipment designs using new and diverse friction materials. This specification replaced the older CD/TO-2 specification. The differences between CD/TO-2 fluids and TO-4 fluids were highlighted in Team News 4.5. Suffice it to say that the differences in viscometrics (shear stability), additive chemistry, and frictional performance are substantial. Whereas a wide variety of oils met TO-2 requirements, only specialized lubricants meet TO-4 requirements. TO-4 fluids are formulated to eliminate transmission slippage experienced with many CD/TO-2 engine oils and to provide significantly improved friction and antiwear performance, resulting in longer equipment life and reduced risk of field failure. TO-4 fluids must be used in all new Caterpillar equipment under warranty, and are preferred for older equipment no longer under warranty. They are also recommended for Komatsu-Dresser powershift transmissions (SAE 10W and 5W-20). Although CD/TO-2 fluids may be used in older equipment, component life may be shortened. Caterpillar does not have a formal approval program for commercial TO-4 fluids. Each supplier is responsible for the performance of its own products. 76 HT/4 Fluid is specially formulated to meet the demanding performance requirements of the Caterpillar TO-4 specification and is the only 76 product recommended for TO-4 applications. The viscosity grade used depends on ambient temperatures and the specific model transmission. For those customers who choose to use CD/TO-2 fluids in older equipment, our primary recommendation is 76 Guardol QLT monogrades. Other 76 products that meet TO-2 requirements are 76 Triton QLT, 76 Firebird HD, 76 T5X Heavy Duty (SAE 15W-40), 76 Hydraulic/Tractor Fluid, 76 Firebird Tractor Hydraulic Fluid, 76 Super ATF, and 76 Multi-Purpose ATF. However, Caterpillar does not recommend the use of multigrade oils containing VI improvers in its powershift transmissions unless they meet the shear stability requirement of the newer Caterpillar TO-4M specification.

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The Caterpillar TO-4M specification defines the minimum performance requirements for the use of multigrade oils in Caterpillar transmissions, hydraulic systems, and wet brakes. Passenger car ATFs, tractor hydraulic fluids, and typical multigrade engine oils do not meet Caterpillar’s shear stability requirement and thus are not recommended for use in Caterpillar powershift transmissions. 76 HT/4 Fluid 5W-20 does not contain a viscosity modifier and thus may be used in Caterpillar powershift transmissions. It is especially formulated for use in low ambient temperatures. European Bus, Heavy-Duty, and Off-Road Transmissions European OEMs such as Voith and ZF typically specify DEXRON -IID or DEXRON -III fluids for their commercial on-highway transmissions. 76 Super ATF is recommended for use in Voith DIWA transmissions while both 76 Super ATF and 76 Multi-Purpose ATF may be used in ZF Ecomat automatic transmissions. For off-road equipment with torque converter transmissions, ZF recommends API CF/SG engine oils, Caterpillar TO-4 fluids (SAE 10W or 30), or DEXRON  -IID/III ATFs. Both OEMs maintain lists of approved fluids. 76 Lubricants Company is currently pursuing both Voith and ZF approvals for 76 Super ATF. A summary of the recommended 76 products for Voith and ZF transmissions is given in Table 6. OEM

Application

Recommended Fluid

76 Product

Voith

DIWA transmissions

DEXRON -III

Super ATF

API CF/SG TO-4

Guardol QLT HT/4 Fluid 10W, 30 Super ATF Multi-Purpose ATF Super ATF Multi-Purpose ATF

ZF

ZF

Converter transmissions for off-road equipment

DEXRON -IID/III

Ecomat transmissions

DEXRON -IID/III

Table 6. European OEM Commercial Automatic Transmission Fluids.

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Multipurpose Tractor Hydraulic Fluids Multipurpose tractor hydraulic fluids such as 76 Hydraulic/Tractor Fluid are specially formulated for use in farms tractors and other equipment using a common fluid to lubricate the transmission, final drive, hydraulic system, and oil-wetted disc brakes. A careful balance of friction modifiers is required to meet the various friction requirements for transmission and PTO clutch durability and wet brake performance. In addition, these fluids require wear protection for transmission gears and hydraulic pumps and extreme pressure protection for maximum final drive gear life. Multipurpose tractor hydraulic fluids have the greatest proliferation of proprietary OEM specifications, principally due to differences in design philosophies and construction materials. When these systems were first being developed, there were no commercially available products that provided the type of performance desired by the equipment manufacturers. Thus, the manufacturers tried to develop fluids that were specific to their own needs. 76 Hydraulic/Tractor Fluid and 76 Firebird Tractor Hydraulic Fluid meet the OEM requirements of all major brands of tractors as well as the requirements for Allison C-4 and Caterpillar TO-2, as listed on the Product Application Sheets. However, since they contain viscosity modifiers and have different frictional characteristics (they are more slippery), they do not meet Caterpillar TO-4 requirements and must not be used in applications specifying a TO-4 fluid. Passenger car ATFs are not formulated to meet all the special requirements of multipurpose tractor hydraulic fluids, and must not be used for farm equipment. For additional information on 76 Hydraulic/Tractor Fluid, please review Team News 4.2. SUMMARY Manufacturers of passenger car and commercial automatic transmissions have specific requirements for their transmission fluids. These fluids cannot be used interchangeably in all transmissions. Differences in frictional characteristics and other performance criteria such as shear stability must be taken into account when recommending the proper fluid. Use of the incorrect transmission fluid may result in poor shift quality and shortened component life. Allan W. Perry Technical Specialist Engine Oils, ATFs