SMJ,
This is copied from the 2002 Nissan Frontier Service Manual:
""Checking A/T Fluid NEMA0030 1. Warm up engine. 2. Check for fluid leakage. 3. Before driving, fluid level can be checked at fluid temperatures of 30 to 50°C (86 to 122°F) using “COLD” range on dipstick. 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 dipstick and note reading. If level is at low side of either range, and fluid to the charging pipe. e. Re-insert dipstick into charging pipe as far as it will go. f. Remove dipstick and note reading. If reading is at low side of range, add fluid to the charging pipe. Do not overfill. 4. Drive vehicle for approximately 5 minutes in urban areas. 5. Re-check fluid level at fluid temperatures of 50 to 80°C (122 to 176°F) using “HOT” range on dipstick. ""
I have found whether or not the Gear Shifter isn't moved through all the gear's that it defininitely make's a Difference in the fluid level on the dipstick. Not only that notice that it give's a Temperature Range to check @ in the cold and hot range. This is basically the same procedure that was given for the '93 4cyl at hardbody that I had for 20 year's and always wondered why the fluid level was different at different time's of the year. Now that I have a Scangauge II with the ATF Temperature Gauge's, I know why now. It is because at different time's of the year the Ambient Temperature is different, and it definitely make's a difference in the Fluid level on the Dipstick, whether using the Cold Range or the Hot Range. When checking the ATF Level @ say 40F and 90F can make a pretty big difference on the dipstick. I wasn't aware of this until I started using the Scangauge II available now for the Newer gen 2 Frontier's. Amazingly in the Winter Time the ATF Temperature rarely get's to 149F Degree's during 20 mile trip to Walmart weekly for groceries. 149F Degree's is the Temperature given to check the ATF Level using the Hot Range on my 2013 4 Liter Frontier King Cab with the 2.937 Rear Axle Ratio. Maybe because the Transmission isn't turning very fast in Over Drive. Only during the Hot Summer Time can I check the ATF Level using the Hot Range @ 149F Degrees. Mine run's really cool, but I'm sure if I was pulling the utility trailer with any kind of weight, it would run hotter.
Only reason I'm bringing this to your attention, is that Nissan say's not to Overfill. Being a Professional Mechanic and a Past Master Tech @ Nissan, You know more about this stuff than I ever will, but wanted to bring this to your attention.
Regards,