Manual or automatic trnsmission?

CHECKING A/T FLUID

1. Warm up engine.
2. Check for fluid leakage.
3. Loosen the level gauge bolt.
4. Before driving, fluid level can be checked at fluid temperatures of 30 to 50°C (86 to 122°F) using "COLD" range on A/T fluid level gauge as follows.
A. Park vehicle on level surface and set parking brake.
B. Start engine and move selector lever through each gear position. Leave selector lever in "P" position.
C. Check fluid level with engine idling.
D. Remove A/T fluid level gauge and wipe clean with lint-free paper.
CAUTION:
When wiping away the A/T fluid level gauge, always use lint-free paper, not a cloth one.
E. Reinsert A/T fluid level gauge into A/T fluid charging pipe as far as it will go.
CAUTION:
To check fluid level, insert the A/T fluid level gauge until the cap contacts the end of the A/T fluid charging pipe, with the A/T fluid
level gauge reversed from the normal attachment conditions.
F. Remove A/T fluid level gauge and note reading. If reading is at low side of range, add fluid to the A/T fluid charging pipe.
CAUTION:
Do not overfill.
5. Drive vehicle for approximately 5 minutes in urban areas.
6. Make the fluid temperature approximately 65°C (149°F).
7. Recheck fluid level at fluid temperatures of approximately 65°C (149°F) using "HOT" range on A/T fluid level gauge.
8. Check fluid condition.
If fluid is very dark or smells burned, check operation of A/T. Flush cooling system after repair of A/T.
If ATF contains frictional material (clutches, bands, etc.), Replace radiator and flush cooler line using cleaning solvent and compressed air after repair of A/T.
9. Install the removed A/T fluid level gauge in the A/T fluid charging pipe.
10. Tighten the level gauge bolt. Level gauge bolt:
5.1 N.M (0.52 kg-m, 45 in-lb)

Fluid recommended is Nissan Matic J or S

You're welcome.

It should be somewhere around the transmission. It is bolted on and you need to remove a bolt to take it out.