SIC 7537 Automotive Transmission Repair Shops


SIC 7537

This category covers establishments primarily engaged in the installation, repair, or sales and installation of automotive transmissions. The sale of transmissions and related parts is considered incidental to the installation or repair of these products.



Automotive Transmission Repair


By the late 1990s, developments in U.S. automotive technology and design ensured that both manual and automatic transmissions were among the most reliable parts of an automobile. But the complexity of the transmission as a system of many precisely interrelated components, as well as the difficulty of diagnosing and correcting faults, meant the problems that did occur were unlikely to be tackled by drivers in their own garages. Instead, this situation created a market for professional mechanics specializing in transmission repair.


In 1998, 10.7 percent of new cars sold in the U.S. came with a manual transmission. This reflected a major shift from the 1970s, when, because of sharp increases in oil and gas prices, manual transmissions dominated the new car market. Manual transmissions were far more fuel efficient, and were standard on small foreign imports, which became popular during the efficiency-aware '70s. But as prices settled and automatic transmissions became more fuel-efficient and increasingly advanced, they rose in again in popularity through the 1980s and into the 1990s.

Routine maintenance demanded the periodic checking and changing of automatic transmission or transaxle oil, and possibly the replacement of the transmission filter. As with engine oil, transmission fluid could be checked by means of a dipstick. The detection of signs of contamination of the transmission fluid, by metal, dirt, moisture, or friction material from internal parts, was an important step because such contamination could lead to rapid wear of parts and to premature transmission failure.

Inspection of the transmission fluid also provided an invaluable guide to the diagnosis of existing or potential problems. Fluid that was milky typically became intermixed with the engine coolant; fluid that was blackened or had a burnt odor indicated serious damage to the transmission; and fluid with a light brown color usually had broken down, which led to a wide variety of further problems.

Manual transmissions required the operation of a clutch mechanism subject to high levels of wear and tear. Among the problems tackled by transmission specialists working on manual transmissions were pulsating or stiff clutch pedals; clutches that grabbed, chattered, dragged, or slipped because of improper clutch adjustment; a binding clutch release mechanism; a broken engine mount; or oil or grease on a clutch disc. Repairs to the clutch often required the removal of drive axles, transaxles, and even entire engines. Other problems found in manual transmissions were noise, leaks...

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