I havnt long owned the car, when i first got it the overdrive did absolutely nothing - the only thing it did do was click as the gearlever pased through neutral with the switch in the 'on' position. Now, after changing the oil and cleaning out all of the filters ( they were in a prety bad state.) it will engage, but to get it to do this you have to prety much let your foot right off the throttle but as soon as you return the pressure to the accelerator it seemes to 'slip' back into the lower gear? The last thing we did was remove the oil again, and on doing so we noticed the 'filings'? Thanks Ceri