Transmission oil manual#

Automatic transmission fluids such as Dexron IV, Mercon IV, and DemlerChrysler MS 9602 are currently used for service. The following automatic transmission fluid classification is obsolete: GM Type A, GM Type A-Suffix A, and GM Dexron. Dispersants are used in ATFs to suspend thermal decomposition and oxidation products. The major role of sulfonates in ATFs is to stabilize friction characteristics. Both detergents and dispersants play significant roles in automatic transmission fluid ATF in additive packages. An automatic transmission requires smooth shifting from gear to gear. In Tribology and Interface Engineering Series, 2003 Transmission lubricants.Ī relationship between GM and Ford classifications is presented in Table 2, Appendix. Because of this, automobile manufacturers would like to use more heat-resistant fluoroelastomers with adequate base resistance for long-term sealing performance. However, temperatures of 150☌ may be attained for considerable periods when vehicles are driven long distances at high speeds. If temperatures are low enough, hydrocarbon elastomers such as HNBR or acrylate perform satisfactorily.

Often a seal must retain lubricants on one side, while the other side is subjected to contaminants such as water, mud, and dust, which can cause problems with corrosion and abrasion. These fluids are extremely aggressive toward VDF-containing fluoroelastomers, and there is no aeration to mitigate the effects of additives. 5 Gear and wheel-bearing lubricants and automatic transmission fluids contain additive packages similar to those in engine oils, but usually more concentrated, since these fluids are not changed at frequent intervals. Seals in automotive transmission systems (including differential, axle, and wheel-bearing seals) operate in severe environments. Jiri George Drobny, in Fluoroelastomers Handbook (Second Edition), 2016 14.4 Compounds for Transmission Seals

Transmission oil manual#

All manual and automatic gearboxes- change after 20000 miles. (5)Ĭhange periods: (only if manufacturer's recommendations not known). ATF fluids must not be mixed with others. They must not be mixed with any other oils. Some synthetic (polyglycol) oils are very successful with worm gears. The above EPs are given for safety if supplier's recommendations are not known. In most cases (except hypoids), straight oils are acceptable. In hot conditions (> 40☌) use one SAE grade higher. In cold conditions (0☌) use one SAE grade less. (2)Ībove are suitable for normal conditions. SAE 80 EP for semi-automatics ATF fluid for autosĪbove only to be used where supplier's recommendations are not available. Additive systems have been developed with properties acceptable to Daimler-Benz, however, and a ‘universal’ ATF can now be blended. The Daimler-Benz requirement is that a fluid should retain its frictional characteristics throughout its life (in other words, throughout the life of the car). GM's latest designation is Dexron III, and the latest Ford specification is Meocon v. Over the years, GM and Ford have progressively raised their levels of demand for oxidative/thermal stability, to cater for cars with higher power and thus greater likelihood of high transmission temperatures. It must preserve all these properties throughout its service life, so as to maintain consistent lubrication performance and gear-change characteristics. Remove frictional heat and cool the whole transmission unit.Īn ATF requires high lubrication performance, high levels of oxidation stability to withstand the locally high operating temperatures, a degree of fluidity that ensures easy operation in cold weather, stable viscosity properties, closely controlled frictional behaviour to ensure quiet, consistent and chatter-free take-up of power in the internal brakes and clutches.

It must: 1.įill the torque converter (or ‘automatic clutch’) and thus convey power from the engine to the gearbox 3.Īct as hydraulic medium by conveying signals from the valves in the control unit to the internal clutches/brakes that engage the gears 4.Įnsure smooth but rapid take-up of power between the friction faces of the oil-immersed clutches/brakes 5.

An ATF has to satisfy several requirements.