Member Credit: Greg

I might be going out on a limb classifying the changing of your manual transmission fluid as a “performance” modification, but considering how use of this stuff will improve your shifts in both cold and hot weather, the classification might not be that far off. I used Red Line D4 ATF in my 1999 Maxima, and the automatic shifts were much more crisp and smooth, so I decided to give the manual transmission equivalent a try. Nissan recommends gear oil of API grade GL-4 and a viscocity of 75W-90 or 75W-85. Red Line MT-90 meets these specifications.

Transaxle oil capacity for the 6-speed is significantly less (roughly half) that of the prior Maxima’s (1995-2001) 5-speed. You will only need 3 quarts of MT-90, and you will not even be able to use all of the 3rd quart.

Not many tools are needed. A 3/8-inch drive ratchet with a 10mm hex bit is all that is required to remove both the drain and fill plugs, which are identical on the 2002 6-speed transmission.

You also need either a funnel with a long (~3.5 feet) flexible hose, or you can string together anything that will give you the appropriate length. I used a large funnel with a hose extension that allowed me to turn the flow on or off (important if the tip slips out of the fill hole!!).

When replacing the drain and fill plugs, it is a good idea (although not totally necessary) to replace the gaskets. These gaskets do not “crush” like the crankcase oil plug gaskets do, so they can be re-used. Price for each from Nissan was $2.21. You’ll need two. A bit steep…

Here is a blowup from the shop manual. Some of you might notice that this transmission looks quite differently than the 5-speed in earlier 4th and 5th-generation Maximas.

This photo (and the one below) should look like the drawing (above). Photo at left was taken from near the left-front wheel, shooting towards the passenger side of the car. The tranny fluid drain hole is visible in the lower right corner of the picture.

Here is the fill hole. Contrary to what some have done, it is not necessary to jack the car up or put it on ramps to do this job. In fact, I do not recommend raising the car, as all of the fluid will not drain out. I put an old rug on the garage floor and did everything lying on my back – it was not difficult at all – you just need good lighting.

Transax-FillHole.jpg (720×480)

Here is another image from the shop manual, with highlights. After draining/refilling the transmission fluid, you should replace both crush gaskets before putting the plugs back in.

Here is the drain (or fill) plug removed.

It only takes 10-15 minutes for all of the fluid to drain out. The 2002 6-speed transmission will give up roughly 2.5 quarts of very brown-looking fluid.

Here is my funnel system, all rigged up. This is actually the most time-consuming part of the whole process. Making sure your setup is good enough so that it will not leak, fall out of the fill hole, or drop down to the floor. I recommend roughly 3-3.5 feet of hose. You fill the tranny until oil pours back out the fill hole. It should take roughly 2.5 quarts. Note, this is half the capacity of prior Maxima manual transmissions.
After performing this simple change, I noticed that all shifts (especially 2nd-3rd, for some reason) seemed much smoother, and engagement was crisp and positive. An extremely worthwhile investment.


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