The phenomenon of transmission failure closely following a fluid change in a neglected unit is no wive's tale. You'll have a hard time finding a service facility that will do the service on such a vehicle without a signed disclaimer of responsibility from the car's owner. Not if they want to stay in business very long, anyway. Almost anyone who's been in the business very long has horror story(s) about ticked-off customers demanding a new transmission after a routine fluid change on a high-miles, no-maintenance transmission causes sudden failure within a very short interval. We can argue all day about the exact failure mechanism, but the scenario is well-known. But it is true, as someone pointed out, that if such a failure occurs after a fluid change, you really haven't lost much, since the trans had to be pretty far gone anyway. Transmissions in good condition aren't harmed in any way by changing the oil, with the one caveat Dick pointed out about older cars which originally had the whale-oil based fluid. The statement that auto trans fluid does not wear out in use is only partially true. The fluid has two distinct functions, lubricating bearings/gears, and transmitting hydraulic forces. The oil does not lose its hydraulic function, but it is subject to shearing forces, and it does undergo chemical degradation, albeit to a far lesser extent than the engine's lubricant, assuming the transmission is not overheated. Thus, over time, its lubricating ability is decreased, hence the recommendation for regular service. And if the trans is overheated, all bets on the quality of the fluid are off. For what it's worth. YMMV. Michael Roger and Michael in San Diego 67 Crown Convertible "Moby" 73 LeBaron Coupe "La Bomba Negra" 56 Sedan