The Hydra-Matic drive fluid was only available at GM dealerships. This fluid had cold-weather performance problems, which led to the need for an improved fluid, the Type "A" fluid, in 1949. This was the world's first automatic transmission fluid, designed for the world's first mass-produced automatic transmission. This fluid was composed of a Group 1 base oil and additives to reduce oxidation, foaming, rust, corrosion, varnish, and sludge buildup. By using the term "fluid" rather than "oil," they hoped to discourage the previously accepted practice of using SAE 20 engine oil. The Hydra-Matic Drive used a specialized lubricant called GM Transmission Fluid No. Released in 1939, the 1940–1949 GM Hydra-Matic Drive was used by the Oldsmobile, Cadillac, and Pontiac divisions. The driver could change ranges with a flick of a finger. In high range, the transmission would start in 1st gear, jump to 3rd, then shift to 4th gear. In low range, the transmission would shift from 1st to 2nd gear and then hold in 2nd. The AST had two driving ranges (low and high). The clutch was only necessary when starting or stopping the car. The transmission was called the Automatic Safety Transmission (AST) because the clutch operation was reduced to one-third of that required by a conventional transmission. The Automatic Safety Transmission was a four-speed transmission that could shift powerfully without needing a regular clutch. The automatic safety transmission used the same seasonal grade of motor oil as the engine for lubrication and hydraulic functions. It was only used during the 19 model years. The automatic safety transmission was first offered as an extra-cost option by the Oldsmobile Division of GM in the fall of 1937 for their Six and Eight models. See the details below for the backward compatibility of each fluid.īefore Dexron: 1937–1967 1937 – Motor Oil ġ940 GM Hydra-Matic automatic transmission fluid There remains a market for older fluids that claim to meet the earlier fluid specifications. Newer 6, 8, 9, and 10-speed transmissions, as well as plug-in hybrid (PHEV) and electric vehicle (EV) transmission technologies, require specialized fluids to operate properly. The newer fluids are not always backward-compatible with previous fluids. GM has upgraded the Dexron's specifications over time. Over the years, the original Dexron (B) was supplanted by Dexron-II (C), Dexron-II (D), Dexron-II (E), Dexron-III (F), Dexron-III (G), Dexron-III (H), Dexron-VI (J), Dexron HP, Dexron LV ATF HP, and Dexron ULV, which is the latest fluid. The original Dexron (B) transmission fluid was introduced on April 1, 1967. Originally, the Dexron name was associated exclusively with automatic transmission fluids, though GM later released Dexron gear oils and other lubricants under the Dexron brand. Like many automobile manufacturers, GM uses transmissions sourced from other suppliers or transmission manufacturers around the world many of these may use their own unique fluid. To be licensed, the product must have a license number that begins with the letters B through J and include a "Dexron Approved" sticker on its container. Not all Dexron fluids are licensed by GM for reselling under another brand name. GM licenses the name and specifications to companies that manufacture the fluid and sell it under their own brand names. The name was first registered as a trademark and later evolved into a brand of GM. Dexron is the trade name for a group of technical specifications for automatic transmission fluid (ATF) created by General Motors (GM).
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |