> In fact, during the 60's when these transmissions were built, the potential of > a lockup converters was well known in the industry. However, everybody > realized that the improvement that such a device would offer did not worth its > cost (because the converter slippage is very low most of the time). In modern > times, the engines lost torque and the requirements in performance increased, > so they started installing high stall converters. Also, overdrive > transmissions became common. Overdrives tend to load the engine at low speeds > where slippage is high. Now, the potential benefits of the lockup are higher, > so they are used on virtually all modern cars. Don't modern cars include some 'either/or' control logic? IOW, first OD is engaged, and then lockup. Lockup is first to let go, then the unit downshifts as needed. > > Now, why did the 440s in 78 had lockup transmissions? Oil crisis may be? As > said, I cannot verify any mileage advantage of my lockup equipped LeBaron. > That is encouraging news for anyone who is concerned about gas mileage who is using an older trans. John