Nissan CVT Transmission

I see a lot of articles and videos that talk about how Nissan CVTs (Continuously Variable Transmissions) are trash and as an owner of one I wanted to share my thoughts.

At the writing of this article, my Altima has 129K miles on the odometer. My car was one of the first ones to come out with the transmission that was redesigned for the 5th generation Altima. Within the first year, I had to take it back to the dealership to get the transmission reprogrammed twice because of two different Technical Service Bulletins (TSBs) that were issued by Nissan in relation to the transmission.

Early Days

Was somewhat freaked when I first got the car. Seeing the experiences that others had, it was clear that there was a defect somewhere, but wasn't sure where. Having a Nissan and paying attention to how they do things, I realized that they have an approach that is similar to other Japanese manufacturers, modeled after The Toyota Way.

Build it, test it, send it out in the real world. If there are issues in the real world, then analyze those and then repeat the process. This is similar to the SCRUM metholodgy that programmers use today when building and maintaining software. The 5th generation Altima was rolled out in May of that year. Mine was built in July of the same year. The members of Nissan Club that had got theirs before mine, had major issues. Some of which, Nissan bought them back because of the transmission issues.

Bad Math

Now I'm not a Nissan engineer, but I do believe that there was some bad math or calculations that were done between what was done on their test course and what was experienced in reality. As a result, real world tests failed and resulted in destroyed transmissions. Belts popping in transmissions with less than 2K miles, that the TCM had a bad math algorithm, and under certain conditions, that algorithm would send the transmission back to its maker (because Nissan requires that dealers send warranty repair parts back to Nissan for analysis). The TSB fixes for the transmissions were to correct that bad path. For those that are not as technicially inclined, they basically applied a software update to the transmission in order to prevent more lawsuits or buybacks.

Change The Transmission Fluid

Now I recognize that there are some situations that transmissions in Nissans do fail. The majority of the failures that I have heard about were due to people failing to change the transmission fluid at the appropriate interval. My thoughts are that the cones that are inside the CVT transmission, can operate within a particular viscosity range of transmission fluid.

As the fluid becomes dirty and breaks down over time, they do not provide the correct amount of pressure to the cones, thus keeping tension on the belt or chain (V6 engines have chains, 4-cylinders have belts) becomes more difficult. In the worse case scenario, too much pressure is applied to the belt, and as a result the belt pops. Not enough pressure could be applied to the belt, and as a result the transmissions slips or in the worse case comes off the cones completely and doesn't break.

Manual Transmissions

When manuals were more common, you didn't have to change fluid in them because they didn't have any. There are some exceptions, like those that use brake fluid or clutch fluid to control the clutch. You would know something was up because you need both of those systems to drive. In addition, the one that uses brake fluid to control the clutch, if the fluid went low, the brake light on the dash would come on indicating a problem.

It seems to me that not changing the fluid in transmissions is still a thing today. Some that manufacturer geared automatic transmissions do not have a problem with theirs because a geared design is more tolerant to pressure changes than a a cone design. However a gear design can fail just as easily as a CVT because they are now making the geared transmissions with 10 or 12 gears and have just as many parts when you combine the gears, clutches, friction plates, and more.

My Keys for Longevity

These are my thoughts on how to get the longest life out of your CVT:

• get the fluid changed per the service interval in your owner's manual
• you can drive it hard, contrary to what Scotty Kilmer may say, but do not always act like you are in a NASCAR race
• monitor when TSBs are released. Manufacturers do not have to notify you about these, but they usually have them posted somewhere that a customer can access.
• when a TSB is released, take your car to the dealership and let them know that you want that TSB performed. If your vehicle is still under warranty, then the repair work will be free.