Why not change the shift direction on the V35? Then they will both be the same..
The Manual mode.. when you push it over it will always go to 4. You have to shift to 5 manually.
On the M35, when it says 4, it means it will use all gears up to 4, same applies to 3 etc...
Does not sound right it getting stuck in a high gear.. It has a computer for the auto box and this should control this.
This gear box does not take the same transmission oil as most older Nissan's. It uses nulon atf/Nissan Matic J
If someone put in Matic D it will kill the gear box.
I would get the oil checked as this may be part of the problem.
If you use the gear box only in manual mode the oil will get very hot as when in manual mode the fluid does NOT go through the radiator to cool. It only goes through the radiator when in Auto mode.
If you overheat the gear box it will not shift down easily.
A transmission cooler is a great addition for our climate and some thing most of us have installed.
Cheers
Andy