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Discussion Starter #1
Has anybody checked out or installed an auxiliary tranny cooler? I had trouble years ago with overheating/failing transmissions and got into the habit of adding another cooler on every vehicle I owned (except sticks of course). I've never had any tranny trouble since, I believe it really helps especially if you're regularly hauling trailers. I only do that occasionally now , but still wouldn't mind getting one, particularly for a CVT that will no doubt be ultra-expensive to repair sometime. I'm planning on keeping my Mo for a long time, and am trying to help wherever possible. I just switched to Mobil One too.

Any ideas or sources, anybody tried a second cooler?
 

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Since the MO has a class III hitch, you can't tow more than 3500 pounds with it. This does not qualify as sufficiently heavy to require an extra tranny cooler. To my knowledge, there is no extra cooler available for the CVT. In any case, the CVT has a much lower operating temperature than hydraulic auto trannies.

You usually see tranny coolers with class IV and up hitches.
 

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An auxilary transmission cooler is a good idea regardless if you tow or not. Even if it reduces transmission fluid temp by 10 degrees, it will extend the life of the fluid and prevent varnish from building up inside the tranny.

It is my understanding that the CVT runs hotter than normal transmissions. Why else would Nissan build in a circuit to protect it from overheating?

I would seriously consider an aux cooler when I change the CVT fluid at 30k (yeah I know, its early but I'm not taking any chances with an unproven transmission).
 

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You're right about the temperature. The regular auto tranny runs at around 175 C and the CVT at 200 C.

I was on the impression that it was the contrary.

There is however no aux cooler designed yet for the CVT and seeing how many are sold each year, I wouldn't hold my breath until it happens.
 

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Discussion Starter #5
An auxilary transmission cooler is a good idea regardless if you tow or not
Exactly. It cannot hurt. Heat is deadly for auto trrannies. Several times I've hooked a largish generic aftermarket auxilary cooler in series with the existing (usually tiny) stock cooler with excellent results (meaning never a problem and the oil stays acceptable -no overheating).

Aftermarket coolers are just a radiator with a couple of hoses/fittings and mounted where they'll get plenty of airstream.

Can anybody think of a reason this might be a bad idea with the Mo?
 

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It seems to me that coolers in general have been proven to work on just about every auto tranny under the sun.
But not this one.

As a scenario, suppose the CVT requires 2 pints of fluid per minute flow at 60 PSI pressure in order to operate properly.
Now assume the addition of "another" cooler, impedes the flow to 24 ounces at 45 PSI.
(IMO there is no way that you can add a cooler without impeding the flow to SOME degree.)
In addition what if the operating characteristics of the CVT are such that the ideal operating temp is between 120 F and 200 F and the addition of your cooler drops the actual temp range to 95 F - 160 F.
Is it not possible that this super secret monkey juice could give you unsatisfactory service from running too cool?

1- Is it possible that in trying to help, you could hurt?
2- Is it not possible that the tech could take one look at that and cancel your warranty?

It is my intention to do everything that Nissan tells me to do with the CVT and nothing more.
Now, if and when Nissan comes out with an auxiliary transmission cooler for the CVT, I will be among the first in line to have it installed.



Homer:1:
 

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Discussion Starter #7
Homer: well said, all of it.

As another, more famous Homer(Simpson) said: 'Patience, my pet"

I'll wait too, no need to risk it.
 

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Just a couple of points on this - first, I agree, until Nissan says an auxillary cooler is needed, no need to try to jerry-rig something up. It could, in fact, cause more harm that help as outlined by Homer.

Second, the tow classification for the Murano is Class III, but at the lowest end of the scale. Class III encompasses the capacity to tow from between 3,500 to 5,000 pounds. The Murano's limit is 3,500. This rating is, in fact, the same as the highest Class II rating. So simply stating that the Murano is a Class III can be slightly misleading.

Third, transmission coolers ARE offered on Class II capable vehicles. How do I know this? Because my GM minivan rated at Class II (i.e., 300 pounds tongue weight, 3,5000 tow weight), is equipped with the tow package that includes, among other add-ons, an oil cooler and an auxillary transmission cooler. These add-ons are also offered on other vehicles capable of only hitting Class II towing max.
 

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It has been stated on this forum the CVT has 3 cooling systems; 1)cooling lines through radiator 2) the "air scoop) and 3) ? ...does anyone know what the 3rd consists of?
 

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Classes also define tongue weight and maybe this is the reason why the MO has a class III (50 pounds extra TW over max in class II). But in any case, and until further notice, there is nothing wrong in pulling 3500 pounds with it without adding ANY extra cooling to the OEM setup.

This is however not true with many minivans (Chrysler especially), their trannies already overexploited by the only weight of the vehicle.
 

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I have never heard of a transmission cooler adversely affecting any transmission - i.e. where lower fluid pressure counteracts the cooler fluid. That said, I believe unless the CVT fluid is really strange and must run at high pressure for the CVT to work, I think a cooler would definitely benefit the transmission. For all you know, a rash of CVT failures might spur Nissan to make an auxiliary cooler standard in the future during the model refreshening update.

I am surprised that with Honda's recent transmission disasters on the Accord, Oddy, TL, CL, etc.. they have not made an aux cooler standard by now.

I have a B&M cooler on my 97 Maxima and zero problems. I run Redline D4 ATF in the Maxima.
 

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I have never heard of a transmission cooler adversely affecting any transmission - i.e. where lower fluid pressure counteracts the cooler fluid.
Me neither but until May 2004, I never owned a SUV built around a CVT before. Manual transmissions do not need extra coolers. This is a new environment, unknown to the vast majority among us and we can only speculate at this point.
 

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The 2005 Toyota Highlander hybrid, which has a CVT, comes with an auxiliary transmission fluid cooler on the tow package.

With Nissan making such a big deal about the CVT and heat (air scoop, CVT overheating protection by the TCU, etc..), I cannot imagine how a cooler would be a negative for this setup. I may consider a B&M cooler when I change my CVT fluid for the first time (although that might not be for a year or more).

Highlander hybrid
 

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The 2005 Toyota Highlander hybrid, which has a CVT, comes with an auxiliary transmission fluid cooler on the tow package. ]The 2005 Toyota Highlander hybrid, which has a CVT, comes with an auxiliary transmission fluid cooler on the tow package.
How many coolers already present on this CVT before adding the tow package? Couldn't find it in the link's text.

I understand that you want the best for your MO but as Homer was saying, "Hell is paved with good intentions"...
 

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SIM said:


How many coolers already present on this CVT before adding the tow package? Couldn't find it in the link's text.

I understand that you want the best for your MO but as Homer was saying, "Hell is paved with good intentions"...

The auxiliary transmission cooler for Toyota's CVT is clearly the external radiator-cooling fin type such as that sold by Hayden or B&M.

Every automatic transmission has a "stock" cooler which is under the radiator coolant tank, but this design can only cool down to whatever temperature the coolant is - in a modern car thats around 185-200F.

I would not even consider the Murano's CVT as having any special "cooler" since the stock one under the radiator is present in every automatic transmission vehicle. The fins on the CVT fluid pan might be considered a "cooler" but when I think of a cooler I am thinking about the Hayden or B&M types.
 
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