Nissan recommends the use of Nissan Matic Fluid D in Nissan Altima cars. Check the automatic transmission fluid level every 15,000 miles and replace as needed. If you usually drive the car under severe conditions, such as trailer hauling, replace the transmission fluid every 30,000 miles.
Park the car on level ground. Raise and level it securely with ramps or jacks. Remove the filler dipstick from beneath the hood and replace it with a funnel. Place a drain pan beneath the transmission fluid pan.
Remove the transmission drain plug with a wrench. Apply pressure to the drain plug while turning it to prevent fluid from leaking out. Allow the transmission fluid to drain. Replace the drain plug and tighten it to 22 to 29 foot pounds with a torque wrench.
Loosen all of the 21 fluid pan retaining bolts. Hold the pan with one hand while removing the bolts with the other. Carefully lower the fluid pan with both hands, making sure you don't spill any remaining fluid. Drain the rest of the fluid into the drain pan.
Find 11 bolts and one nut that attach the filter assembly to the transmission. These are different lengths, so pay attention to their locations as you remove them. Take the filter off the transmission. Check for debris, as this could indicate a problem with the transmission.
Look for the O ring that attaches the filter tube to the transmission. Make sure it comes out of the transmission when you remove the filter. Wipe the mounting boss of the filter with a clean dry cloth. Rub a bit of petroleum jelly on the O ring, just enough to coat the surface.
Locate the two magnets on the transmission pan and clean them. In addition, remove the old gasket from the pan with a scraper. Use solvent to clean all the sediment from the transmission pan. You may use a lint free cloth soaked in solvent if needed.
Push the filter tube back into the mounting boss, making sure it's sealed. Install a new filter and replace the bolts and nut in their original locations. Tighten the bolts to 5 to 6 foot pounds.
Put the new gasket on the transmission pan and align the holes to make sure you have the correct gasket. Remove the gasket and apply a few drops of adhesive. Replace the gasket on the transmission pan and realign it before the adhesive dries. Put the pan on the transmission and replace the bolts. Finally, tighten the bolts with a torque wrench to 5 to 6 foot pounds.
Return the Altima to the ground, but make sure the car is still on level ground. Refill the transmission with new fluid. Only add a small amount at a time, while checking the fluid level.
Start the engine and shift the transmission through the gears, ending in "Park." Check the fluid level again, and adjust as needed.
