[Bargeld]

How many miles on it currently?

What is "standard trans fluid" when you say "The CVT was at some point serviced by the previous owner with standard trans fluid." NS2, NS3, or standard automatic trans fluid, off the shelf of an autozone?

There are a couple of opinions floating around the juke forum with regards to adding the cvt coolers. Personally, my best recommendation for longevity is to leave it alone and just service the cvt fluid every 30-35k miles. Others will say to add the cooler, depending on where you live and/or if you are already showing signs of wear or limp modes. In most cases, adding the cooler is a band-aid for a cvt that is already on its way out. Otherwise, the owner wouldn't be asking about it.

In some rare cases (sounds like your case) the idea of adding the cooler is 100% proactive before any deterioration has occured. In which case just make sure the correct fluid is in it, then drain and fill as often as is economical and convenient.

Others with better input and knowledge than I can offer should be along shortly.

Welcome!

(Also, this may be better as your own thread vs piggybacking on existing).

 

[ShadowDemon]

Thanks.
To answer your question, the Mo has 242k miles on it, the transmission is not original to the vehicle and I have no idea how many miles are on the current transmission. This vehicle was heavily abused.
Yes, I'm trying to be proactive with the cooler, based on knowledge of the heat issues with these as I've read about in many different forums. Very few people know much about the technical information.
The fluid appears to be standard automatic fluid. I used a Mobil product that would be in regular transmissions not the CVT ns2 or 3 fluid. I've already been told by a few people that I should use the Nissan CVT fluid. I'm curious about whether this type of thing has been tried in order to resolve the overheating issue, as mine will be worked pretty hard (steep hill climbs ( 30 degree slopes)on loose dirt, carrying loads of 1k+ lbs ~I'm building a house in a remote area where smaller cars and large trucks are unable to access).
I guess my main concern is that if the standard transmission fluid would be to thick for the pump, retain to much heat even after going through the coolers, and if the clutch or torque converter may fail from the regular auto transmission fluid. I don't know anything about comparison of CVT fluid vs auto trans fluid.

 

[Bargeld]

Using the Juke as the example, if your model specifies NS2 and you use NS3, damage will occur at some point. The different fluids are very specific to each transmission.

XTRONIC CVT Continuously Variable Transmission | Nissan USA

Seamless shifting, constant power. Learn about the advantages of Nissan's game-changing CVT technology over traditional automatic transmission.

www.nissanusa.com

The physics occurring in a CVT are VERY different than a traditional auto trans. The inquisitive side of me wants to know how long the CVT will last on standard A/T fluid. It will get destroyed. The question is how long.

I mean, you can pour salt water in as CVT fluid and it will drive for some period of time, the question is just "how long".

 

[kev604]

Can't believe someone would put regular transmission fluid into a CVT transmission thought I've heard it all WTF you can pretty much kiss that CVT goodbye and people ask me why I don't like buying used cars.

 

[ShadowDemon]

Yep. Thanks for the responses.
I'm done with this thread and forum. If this is the kind of unreasonable response I get from a very basic question there's no need for any further explanations to my questions.
I agree with the the need for CVT over regular ATF. I was looking for more of a technical response regarding my questions. Given that this was a topic new for me.
Your right kev604, this is what happens when you buy used. That's just life. Now, if you'd been able to explain more technically why CVT fluid is better than ATF when the trans has been modified, and not just because the manufacturer said so, your input could have been considered intelligent.

 

[squirtbrnr]

1) CVT is not an AT. Do not refer to a CVT as an AT. about the only thing a CVT and AT share in common is the pressurization of a fluid, the torque converter and Limited Slip Diff (if it has one).
2) google is your friend. There are fluid analysis, MSDS docs, and more technical data available on CVT fluid and from the manufacturers too.
3) This is an open forum. You posted more than just a question, your expectation should have been to get a wide array of responses, some of which you may not agree with.

Now on the topic of fluid, CVT fluid assists grip between the pulley surfaces and the belt. Nearly all of the grip is from the teeth on the belt elements against the pulley and the pressure of the oil pump holding the pulleys at the correct ratio. This added grip is provided by friction modifiers (additives) and other viscosity modifiers that make it more than just an oil. It also is a coolant by removing heat from critical components such as the solenoids, pulley assemblies and bearings, etc through the use of other thermal compounds. It also has surface protectants like anti-wear and anti-oxidation additives which protect the belt and pulleys from the metal to metal contact and heat produced.

As for ATF, it's pretty much just an oil of a specific viscosity. Sure it lubricates and maybe cools, but its main purpose is to actually shift gears.

CVT fluid does so much more. It is the main work horse aside from the actual belt and pulleys. If the fluid degrades, loses any one of its properties, or is even filled to an improper level, the CVT can and most likely will experience premature wear resulting in failure. The question is when, not if. AT fluid does not contain the extra additives for a CVT to properly function. The CVT is trying to adapt to the AT fluid, but ultimately will slip, and the first sign of limp mode means it has slipped and the CVT is on its way out.

 

[kev604]

your input could have been considered intelligent.

How intelligent was it to put regular AT fluid into your CVT transmission to begin with???

 

[pboglio]

Yep. Thanks for the responses.
I'm done with this thread and forum. If this is the kind of unreasonable response I get from a very basic question there's no need for any further explanations to my questions.
I agree with the the need for CVT over regular ATF. I was looking for more of a technical response regarding my questions. Given that this was a topic new for me.
Your right kev604, this is what happens when you buy used. That's just life. Now, if you'd been able to explain more technically why CVT fluid is better than ATF when the trans has been modified, and not just because the manufacturer said so, your input could have been considered intelligent.

Everyone is trying to be helpful. @squirtbrnr & @Bargeld explain it well.

Technical response is great but at this point your transmission is in serious trouble and you don't seem to realize that. You made some critically poor decisions in assuming the viscosity was incorrect while second guessing Nissan and switched to an ATF fluid. I'm guessing based on your description that you don't know how to fully purge the transmission of fluid which is probably what saved it from total destruction. There is most likely 50% CVT fluid still left in the transmission mixed with the ATF.

Your 2005 Nissan Murano takes NS-2 fluid for the CVT, no other substitutions are recommended.

Factory Service Manuals

Trouble loading the file? Visit this page to find additional Nissan, Infiniti, and Datsun factory service manuals.

www.nicoclub.com

The ATF fluid is proven to produce a lower COE (coefficient of friction) when used on a CVT pushbelt application, I have the data somewhere. The CVT run what could be termed a friction modifier which increases the COE to limit pushbelt slippage and reduce clutch shudder. The CVT fluids also run a high pressure lubricant/anti-scuff additive to protect the pulley belt & pulley's. There is also an anti-foaming agent added to keep the oil air-free while the chain whips the oil in the sump and attempts to aerate it. Keep in mind the CVT are going to run at a higher operating temperature than an AT transmission which is more of a design fault or limitation. The ATF fluid doesn't have to manage a constantly slipping steel pushbelt, the NS-2 fluid is designed for CVT belts dipping thru the sump, the NS-3 CVT don't dip the belt/chain and run more oil injectors to lubricate/cool the belts. What the AT and CVT share are the planetary gear trains, valvebody, forward/reverse clutches, bearings, torque converter, etc. They are almost identical in general construction. The AT runs more clutches in the clutch packs while the Nissan CVT typically have fewer. It's the CVT pushbelt & pulley's where they mainly differ. So in reality you cannot run a slick ATF fluid on the CVT primarily because the belt & clutches will slip. That is probably the answer your looking for. This is similar to running a slick synthetic engine oil in a manual transmission. The manual trans fluid is thicker for better gear shock protection but also has a friction modifier to allow the synchro packs to lockup for proper shifting.

But this is academic, you should be running NS-2 fluid and there isn't any debate on that.

 

[pboglio]

Here, read pg 15-16 of the attached document. This'll answer some of your questions. I'll credit @chidog for sourcing this white paper as it was a very good find.

You can see the chemical composition chart & percentage in Table 1. Zinc is used as a high pressure lubricant/anti-scuff additive as an example. The remaining additives are anti-oxidant, anti-foaming, etc. In Table 1. you can also see the difference in the viscosity index. The viscosity is having a direct impact on transmission efficiency and oil pump losses in Fig. 6.

From this you can see that Fluid A (ATF fluid) has a torque capacity index of 1.25 where Fluid D (CVT fluid) is closer to 1.4-1.45. This directly relates to the torque holding capacity of the transmission and the CVTF fluid is the clear winner here. I've mentioned that the ATF and CVT fluids are basically doing the same job for the clutches, bearings, valvebody, & torque converter which is: cooling, lubrication, & hydraulic pressure control. But the CVT friction requirement for the pushbelt is even higher to prevent slippage. The zinc additive is much more critical for CVT as there is direct sliding metal-metal contact of the pushbelt and pulley cones when they do eventually slip.

What this paper doesn't tell you is the durability or longevity because it's not a field trial experiment on an actual CVT transmission. An ATF fluid that has a lower torque capacity is going to slip more. If you factor in no additional zinc or moly-disulfide additive then there will be greatly reduced protection when it does slip, which will be often. This is the worst situation to have on a CVT. It "might" be theoretically possible to say you could run an ATF fluid but it would be unwise to do it. Without a zinc additive for high pressure lubrication the CVT pushbelt life will be greatly reduced. So, no your CVT probably won't blowup immediately and fuel economy might not even be affected in the short term. But Nissan are basically telling you without question to run an NS-2 fluid because it's specifically formulated for your year/make/model vehicle. Make sense? This is as technical an explanation as I can provide and the paper pretty much spells it out if you care to analyze it.

Make your own informed choices but an ATF fluid isn't the solution, the NS-2 compatible fluids are. I ran AMSOIL CVT fluid and had great success with it but it's both NS-2 & NS-3 compatible. AMSOIL is 100% synthetic, has improved anti-scuff & anti-shudder resistance, and much higher torque holding capacity.