Nissan Dayz CVT 660CC

If you swapped out the gearbox are you saying that you swapped out the CVT?

As they say, this is a teaching moment. I feel bad that you used the wrong transmission fluid for your Nissan but I do have to tell you that when the automaker tells you to use, say, Dexron, for instance, you use Dexron, you don’t use anything else. There is a reason for the instruction and the reason is that the transmission and the transmission fluid are meant to work together.

If you put in the wrong fluid, then you risk damaging or destroying the entire transmission. I can understand how it is possible to go to an auto parts store and ask for transmission fluid and having the clerk point to a rack of fluid as he is busy trying to answer the phone and other customer questions. And, you, perhaps not knowing that there are specific types of fluid made for continuously variable transmissions (CVT) just pick up a bottle or two of fluid labeled “transmission fluid,” figuring you can use it.

Unless it is labeled CVT transmission fluid then you can’t use it in your vehicle. What I suspect happened next is that your transmission, not having the proper fluid to not only protect it but also make it operate properly and to lubricate it as well, slowly began to destroy itself from within.

More than likely all of the speed-specific bands that tighten, providing the continual linkage — they loosen when the particular gearing isn’t used, though most of the time the entire drivetrain is engaged — needed are no longer working correctly and you now have a vehicle with an engine and wheels and the whole nine yards. The only problem is that like a vehicle with a normal transmission that has gone your Nissan is just sitting there engine on with nothing happening or nothing much happening.

Now, I can’t honestly say what mechanical damage may have been done to the engine. However, I can say this much and it is that you had better think that it’s likely you will have to replace the entire CVT, at a cost of about $4,000. There’s nothing much else for it, except another vehicle, but, I don’t think you need not go that far. A rebuilt transmission should take care of things.

Thanks for the update, it gives me a bit more to go on. Here’s what I would suggest. You mention that it “goes uphill” and sometimes works “with the AC on.” That tells me that there is some life in the CVT and that it may just be possible to revive things with a bit of work.

My next suggestion is to either get an OBD diagnostic tester and plug it into the diagnostic plug near the kick panel. I would then suggest running the car for a time in whatever modes you can to make it move so that we can get some information about what ails the transmission. The OBD tester — they are available very inexpensively — should give you a range of codes that should, at least, give you an indication of where the problem is.

From my experience, it sounds like there are several problems confronting your Nissan. It is more than likely more than one set of gears in the main body of the transmission are shot. The good news is that they can be rebuilt with time and patience. The bad news is that it will tie up your Nissan and it can get costly — though likely less than a new CVT — if you have to rebuild very much more than half of the transmission’s main parts.

Again, your first step has to be a diagnostic one so you can see what might be going on. Your next step should be getting a qualified technician involved who can read the diagnostic codes or who has the software that can read the codes. Then, you can set up a strategy for your Nissan’s repair with the tech.

Now, I don’t know exactly how much of your CVT is salvageable but you may be lucky and find it is not as bad as it seems. It’s just that you need someone to get in there with you to not only give you the information you need but also to get you going in the right direction with repairs.

Something just struck me as I read your answer to my last suggestion and it is this: Can you afford to take the Dayz into a service shop to have the engine looked at? You keep telling me the engine is noisy and I am wondering if there may not be a mechanical problem for your Nissan’s problem?

If you can, I would take it over to the service area and have the entire driveline, including the engine, looked at and it could be that the problem is there.