I have a nissan micra W reg. The car was working fine except for over heating. I have bought the car 4 months ago to teach my mrs how to drive and the ca only drive around the street and water had always been topped up each time the temperature rises.

First I noticed the engine oil had turned whitish/yellow and the transmission oil black and the engine warning light was blinking then later the car will only start for few seconds the switch off itself.

I did research about the fault and did as instructed on some useful informations by removing the blue fuse inside the fuse box by the driver right foot, start the car the car and let it go off itself then reinsert the fuse which works then the car starts and stay on rolling, then I drained both the engine oil and transmission oil, replaced the engine oil and the transmission oil with a normal transmission fluid and not CVT or DEX III as I don't know the differences or which one the car actually requires and if there was any difference. The Transmission fluid colour I used is more same colour as the engine oil or slightly different (Triple QX EP90 Transmission Fluid 5 Litre).

Now the car starts normal, all warning light now clear from dashboard but the only problem remaining is that the car would not drive when put in D, D1 or R but note that the Reverse light does come on when in R. The car revv normal and the engine sound good but the speedo doesnt move at all when i revv the engine.

Can anyone help what could be the cause why the transmission won't engane or move on D, D1 or R?