There is a transmission oil filler/measurement plug that must be removed to check the oil level. If the vehicle is raised to allow access to this plug, make sure it is securely supported - do not crawl under a vehicle supported only by a jack.
Note: The vehicle must be level to properly check the oil level.
1. Remove the transmission plug, insert your little finger into the plug hole and feel the oil level. It should be near the very bottom of the plug hole.
2. Remove the filler/level gauge plug (indicated by the arrow) and check the oil level with your little finger. It should be near the bottom of the hole in the plug - if it is lower, add oil.
The material is taken from a web resource: www.NissanBook.ru
3. If it is not, add oil through the hole in the plug using a syringe until the oil starts to flow out of the hole. On some late model manual transmissions, the automatic transmission fluid is used. These transmissions usually have a symbol next to the filler/level gauge plug.
4. Install the plug and tighten it securely. After a few kilometers, check for fluid leaks.
5. If you notice that your transmission requires frequent topping up, this may simply be due to leaks that should be identified and fixed before serious problems arise.