Spot on! Thanks again for your help.
For those wondering and for those who come across this thread, the info below may help.
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The later model D40 (YD25DDTi - 140kW) transmissions are no longer fitted with an auto transmission dipstick. On older models the dipsticks are located near the engine oil dipstick and require the removal of a 10mm (head size) bolt to allow for the stick to be extracted.
Whilst the Nissan Factory Service Manual uses the provisions of special service tools for checking the A/T Fluid, there are other ways around this.
- Ensure that the Automatic Transmission fluid temperature is warm, 40 degrees (celcius) to be exact.
- Underneath the car, locate the automatic transmission pan. It is the pan directly underneath the transmission.
- Located in this pan are two bolts. One being a 17mm diameter bolt towards the back of the pan (rear of the car) and a bolt that requires a 5mm Allen Key for removal - this particular bolt is the 'check' bolt & the one that we will refer to for the rest of this process.
- On the drivers side of the transmission above the right hand edge of the pan is the provision for a dipstick. Remove the 10mm bolt that is closest to the bracket holding the selector cable (there is an o-ring on this blanking plate - be sure not to lose it!)
- Proceed to fill the transmission whilst the vehicle is running, crack the 'check' plug and remove, if there is a steady stream of fluid, the transmission is 'overfull'. Leave the CHECK plug removed until the steady stream becomes a small trickle.
- Proceed to reinstall the dipstick blanking plate. Refit the CHECK plug and ensure that all excess fluid is removed, road test the vehicle and recheck the areas in which you worked for any signs of leakage.
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Whilst these steps may not be considered the correct way - but Nissan also state that the oil in these auto gearboxes are life long. Having dealt with transmissions heavily in the past, I don't believe in LIFE LONG oils and thus seek a way to change out the old oil once it has reached the end of its serviceable life.
For the note. I should mention that my car (the one I performed the above procedure on) is a 2012 D40 Navara ST fitted with the YD25DDTi 140kW engine. At the time of fluid flush and level check the car had travelled 55,908kms.
Hope this helps someone out along the way!!!