[Wolfgang Huang]

After 170k miles, I decided to change the CVT fluid for the first time. I know it's long overdue, but the original fluid still looks fairly clean, and the deterioration number is still under 20k. And the procedure is never very clear to me. Reading the posts, it seems that quite a few DIY'er did it by draining the fluid from the drain plug, and then filling it to the level.

I plan to follow the procedure in the Service Manual:
1. Warm up CVT fluid by driving the vehicle for 10 minutes.
2. Drain CVT fluid from CVT fluid cooler hose (return side) and refill with new CVT fluid at CVT fluid charging
pipe with the engine running at idle speed.
3. Refill until new CVT fluid comes out from CVT fluid cooler hose (return side).
About 30 to 50% extra fluid will be required for this procedure.

What's not clear to me is which of the 4 hoses attached to the CVT cooler is on the "return side". There are two hoses on the top of the cooler and two on the bottom. I assume two carry coolant and two, CVT fluid. The diagram (in attached one-page PDF file) does not indicate which is the return hose. I assume the two labeled as "To radiator" are the coolant hoses, which leave No. 12 and the other unlabeled one as possibly the fluid hose, but which one is on the "return side"?

Or, am I better off using the alternative method through the drain plug (which also requires less fluid, but less thorough)?

 

[Cryogenix1]

I was also in the dark as to which line was which on my 2003, and I decided to play it safe and go the drain plug route. However, I do recall watching a YT clip back then where someone did their 1st Gen using a pump to extract the CVT fluid via those lines and then refilling it. I'm sure you could find it if you looked around.

When I replaced my radiator, both small hoses on the bottom of the radiator dripped CVT fluid once disconnected. I didn't check, but the bottom of the radiator (or maybe the bottom-side) might actually have an arrow to indicate direction of flow.
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An online search offered this "expert" advice, which makes sense...

The easiest way to determine which transmission line is the return is a simple test. Chock the wheels of the vehicle, step on the parking brake, and then start the motor. Keep your foot on the brake pedal and shift into drive for about 15 seconds. Then shift back into park and turn off the motor.

Under the vehicle one of the lines will be warmer than the other. The cooler line would be the return line.

 

[Cryogenix1]

This was the video I watched... Looks like the return line is the one on the driver-side (far right of the bottom of the radiator as you're looking at the front of the car).

 

[Wolfgang Huang]

Thanks! I got it all wrong then. I thought the hoses connected to the radiator carry antifreeze.

 

[I need coffee]

2. Drain CVT fluid from CVT fluid cooler hose (return side) and refill with new CVT fluid at CVT fluid charging
pipe with the engine running at idle speed.
3. Refill until new CVT fluid comes out from CVT fluid cooler hose (return side).

The thing you want to be careful with here is I don't think you can replenish the fluid through the dipstick tube fast enough to replace the fluid that's pumped out by the oil pump while the engine is idling and you definitely don't want to run the oil pan dry and have air get sucked into the pump. You will likely have to turn the engine off after a few seconds, refill the CVT fluid, and then restart--doing this until new fluid comes out. I do recall seeing someone on YouTube use an electric fluid pump through the dipstick to add new fluid, in which case you probably could keep the engine running while replenishing with new fluid.

 

[Wolfgang Huang]

The thing you want to be careful with here is I don't think you can replenish the fluid through the dipstick tube fast enough to replace the fluid that's pumped out by the oil pump while the engine is idling and you definitely don't want to run the oil pan dry and have air get sucked into the pump. You will likely have to turn the engine off after a few seconds, refill the CVT fluid, and then restart--doing this until new fluid comes out. I do recall seeing someone on YouTube use an electric fluid pump through the dipstick to add new fluid, in which case you probably could keep the engine running while replenishing with new fluid.

I thought about this before. The question is, will a few minutes of the low (or high) CVT fluid level matter if the transmission is in idle (Park)? It's not like an idling engine where every part is still moving. In park, I suppose most parts in the transmission are not engaged or moving.

Your point is valid. I will see how fast the fluid drain out on the disconnected line with a marked 2-gallon water bottle, and try to keep up on the filling side. If I'm too far behind, I will turn the engine off.

 

[I need coffee]

I thought about this before. The question is, will a few minutes of the low (or high) CVT fluid level matter if the transmission is in idle (Park)? It's not like an idling engine where every part is still moving. In park, I suppose most parts in the transmission are not engaged or moving.

If the engine is running then the transmission oil pump is pumping and you don't want it pumping air.

Your point is valid. I will see how fast the fluid drain out on the disconnected line with a marked 2-gallon water bottle, and try to keep up on the filling side. If I'm too far behind, I will turn the engine off.

If you get a good idea of the flow rate (e.g. X seconds/quart), be sure to update the thread. That would be good info to have for anyone else that wants to service the CVT fluid this way.

 

[Cryogenix1]

I thought the hoses connected to the radiator carry antifreeze.

FYI, some of the YT comments for that video state the actual lines are reversed from what the video indicates, which apparently created a big fluid mess for those who tried doing it as described. I wouldn't rely on the video but would try the "touch" method to see which line is cooler.

Incidentally, in case you've never read about this, some owners who did CVT flushes at higher miles ended up with severe problems with their CVTs. A simple pan drain and fill may be better for higher-mileage CVTs, especially ones whose fluid hasn't been changed in a long time. The potential consequences on this type of fluid replacement process might be the reason why Nissan abandoned it in later Gens in favor of the simple drain and fill.

With your high mileage it would be a good idea to drop the pan and check the magnets and check/clean that internal metal filter.

 

[PaulDay]

With your high mileage it would be a good idea to drop the pan and check the magnets and check/clean that internal metal filter.

I would do this first and then fill the pan up with CVT fluid before starting your flushing procedure. I would also add an extra quart before starting, to give bit more of a buffer.

This is basically what I did on my wife's '13 RAV4, which also has a "sealed" tranny. Final CVT fluid level is even checked the same way, 114 degrees, remove the drain plug and let excess CVT fluid drain out.

I plan on doing mine within the next few months at 60K miles. I'll be dropping the pan, replacing all filters, filling with CVT fluid and doing the flush utilizing the CVT return line as the drain point. I'm also going to try and video document the procedure.

Please let us know the final return line location, hopefully with a picture or two when completed.

Good luck.

Have a good day.

 

[Cryogenix1]

Yeah, there's no point putting in clean fluid unless you know for certain the valve body filter isn't clogged, the magnets aren't caked with shavings and the pan isn't coated with sludge. Especially if using costly Nissan fluid...

It doesn't take long at all to drop the pan to assess things. We'll worth the time and effort, even if doing so was difficult. Adding new fluid without first inspecting within the CVT pan would be like filling a hole in a tooth without first checking for caries.

 

[Wolfgang Huang]

So I just tried to see the temperature difference between the two radiator lines using the method in Cryogenix1's post. I can't honestly say that I feel the difference. I tried twice, first after 15 sec of running on D, the second time, 30 sec on D. Maybe the weather is too cold here (42 degrees F). Even using an infrared thermometer, the difference is unreliably small (both on the metal bends and on rubber lines, around 46 degrees.

In the attached photo, the red circles mark the two lines connected to the radiator/CVT cooler.

 

[Wolfgang Huang]

Back to the YT video, I think he got it right. He connected the radiator to the dumping bottle and fed the new fluid to the CVT. Attached page has a diagram labeling the inlet and outlet lines on the radiator. The one on the driver side is the outlet of the radiator feeding the CVT. He dumps the fluid from the outlet and pumps the new fluid to the CVT.

However, I am now rethinking that I may just do the drain plug and oil pan/filter cleaning rather than the complete flush. I supposed I will need a new gasket for the pan. I will call the dealer Monday.

 

[MuranoSL2003]

So I just tried to see the temperature difference between the two radiator lines using the method in Cryogenix1's post. I can't honestly say that I feel the difference. I tried twice, first after 15 sec of running on D, the second time, 30 sec on D. Maybe the weather is too cold here (42 degrees F). Even using an infrared thermometer, the difference is unreliably small (both on the metal bends and on rubber lines, around 46 degrees.

In the attached photo, the red circles mark the two lines connected to the radiator/CVT cooler.
View attachment 57731

Maybe try checking the temps after driving and it's warmed up. I would think the return line should then be noticeably cooler due to the fluid passing through the radiator.

 

[Cryogenix1]

That's exactly what I was going to suggest. The "expert" tip wasn't brand-specific, so maybe that test works great for some vehicles but not all of them

 

[Wolfgang Huang]

I have already put the shield back. I will try it again when I do the fluid change (hopefully soon). I will use the drain plug, remove the pan and filter for cleaning, and disconnect the two lines from the radiator to let out as much old fluid as possible before I add the new.

 

[il Vetri]

After 170k miles, I decided to change the CVT fluid for the first time. I know it's long overdue, but the original fluid still looks fairly clean, and the deterioration number is still under 20k. And the procedure is never very clear to me. Reading the posts, it seems that quite a few DIY'er did it by draining the fluid from the drain plug, and then filling it to the level.

I plan to follow the procedure in the Service Manual:
1. Warm up CVT fluid by driving the vehicle for 10 minutes.
2. Drain CVT fluid from CVT fluid cooler hose (return side) and refill with new CVT fluid at CVT fluid charging
pipe with the engine running at idle speed.
3. Refill until new CVT fluid comes out from CVT fluid cooler hose (return side).
About 30 to 50% extra fluid will be required for this procedure.

What's not clear to me is which of the 4 hoses attached to the CVT cooler is on the "return side". There are two hoses on the top of the cooler and two on the bottom. I assume two carry coolant and two, CVT fluid. The diagram (in attached one-page PDF file) does not indicate which is the return hose. I assume the two labeled as "To radiator" are the coolant hoses, which leave No. 12 and the other unlabeled one as possibly the fluid hose, but which one is on the "return side"?

Or, am I better off using the alternative method through the drain plug (which also requires less fluid, but less thorough)?

Here's the procedure my transmission shop used.
After warming the fluid, remove drain plug then drain the fluid from the pan.
Remove the pan, then remove the magnets in the bottom of the pan. Thoroughly clean pan and magnets.
Remove external filter than replace with a new filter element.
Remove then replace strainer. There is a new style strainer that may require a bracket to help retain it in the pan.
Replace pan with a new gasket, then bolts as required.
Add approximately 5 quarts of NS3 CVT fluid then start the engine bringing transmission up to operating temperature.
Check level after moving shifter from Park to Drive and back to Neutral. Top off as needed.
I used Amsoil CVT NS3 fluid.

 

[Wolfgang Huang]

Here's the procedure my transmission shop used.
After warming the fluid, remove drain plug then drain the fluid from the pan.
Remove the pan, then remove the magnets in the bottom of the pan. Thoroughly clean pan and magnets.
Remove external filter than replace with a new filter element.
Remove then replace strainer. There is a new style strainer that may require a bracket to help retain it in the pan.
Replace pan with a new gasket, then bolts as required.
Add approximately 5 quarts of NS3 CVT fluid then start the engine bringing transmission up to operating temperature.
Check level after moving shifter from Park to Drive and back to Neutral. Top off as needed.
I used Amsoil CVT NS3 fluid.

Thanks! I will basically do the same as listed except use NS2 fluid as it's recommended for the 1st generation. NS3 may have a lower viscosity for newer CVTs. Also, there is no external filter on my 2005 model.

 

[Cryogenix1]

Also, there is no external filter on my 2005 model.

Unless you got an oddball car, there should be a cylindrical paper filter in the center of the CVT cooler. Nissan dealerships never seemed to have a listing for that filter and O-ring for the 1st Gens, but it was serviceable using aftermarket parts. It's not the easiest to get to and remove, especially if those bango bolts are stuck and end up breaking on you. There was one YT video that showed the process, but it's been removed. There might be another if you search enough.

I had 280,000 miles on that filter and sludge and tons of shavings in the pan and my car ran relatively normal, so with your lower mileage you might pass. If doing it 100% you'd want to replace that filter before adding new fluid.

https://www.nissanmurano.org/threads/cvt-oil-change.227823/#post-779123

 

[Wolfgang Huang]

Unless you got an oddball car, there should be a cylindrical paper filter in the center of the CVT cooler. Nissan dealerships never seemed to have a listing for that filter and O-ring for the 1st Gens, but it was serviceable using aftermarket parts. It's not the easiest to get to and remove, especially if those bango bolts are stuck and end up breaking on you. There was one YT video that showed the process, but it's been removed. There might be another if you search enough.

I had 280,000 miles on that filter and sludge and tons of shavings in the pan and my car ran relatively normal, so with your lower mileage you might pass. If doing it 100% you'd want to replace that filter before adding new fluid.

https://www.nissanmurano.org/threads/cvt-oil-change.227823/#post-779123

Are you talking about the part circled in red? I can't seem to find anything in the FSM on this part or on the existence of the filter.
By the way, I have not done anything yet other than purchasing 8 qts. of NS2. It's too freezing cold here to work on it.

 

[Cryogenix1]

Yes, the part circled in red is the CVT cooler. I'm tired but did a few searches and haven't found any footage of someone taking apart that cooler to reveal the paper filter. But here's a video that shows the 1st Gen and someone repairing broken banjo bolts.