Posted: 5/26/2008 3:26:02 PM EDT
Drive it in O/D all the time, or highway driving only? This has always baffled me. I just bought a 2001 Ram 1500, and it has an overdrive button.
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Yup. If towing or hauling heavy loads, the transmission may hunt from third to fourth gear. This builds up heat, and excessive heat is bad juju for automatic transmissions. Locking out overdrive helps minimize this. |
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Info I found on the 'net: ---------------------------- ATF will provide l00,000 miles of service before oxidation occurs under normal operating temperatures of about l70 deg F. Above normal operating temperatures, the oxidation rate doubles (useful life is cut in half) with each 20 deg increase in temperature. The approximate life expectancy at various temperatures is as follows. Degrees F Miles 175 100,000 195 50,000 212 25,000 235 12,000 255 6,000 275 3,000 295 1,500 315 750 335 325 355 160 375 80 390 40 415 Less than 30 minutes This information clearly shows why ATF coolers and the various maintenance intervals are recommended for severe usage. Above 300 deg F, the metals inside the transmission will warp and distort in varying degrees depending on the severity of the overheat. -------------------------- My ScanGauge II shows me my transmission temperature. No mods necessary. About $170 or so, widely available. eBay, Amazon, etc. |
