Re: 06 Mariner O/D off light on
If you haven't done so already, I would suggest you take your vehicle in for analysis. The O/D light can come on to signal internal problems that can get much worse if ignored. If it was shifting fine with no flare[engine rev] between gears, you may get away with replacing one of the solenoids. Heat is the killer in automatics, as it hardens the seals in the servos and clutch packs, making them apply 'softer', causing more slippage and more heat. If you haven't driven it in traffic a lot, and have mostly highway miles, the transmission can last a long time, but does need the fluid drained and refilled at regular intervals. There is no disposable filter as old transmissions had, just an internal screen that is not serviceable w/o disasembly.