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Discussion Starter #341
If you have a log file send it And I’ll take a look.
 

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Discussion Starter #342 (Edited)
Here is a little clip on the JF016E from an Altima 2.5L 2013/2014 with 39k miles.


In the video the belt is shown to have slipped and caused surface damage to the pulleys. If you listen at 12:18 he mentions the forward clutches are "no good", this is at 39,000 miles mind you. However, the real problem is that the oil pump flow control piston jammed up, see 12:59 as he goes into detail, same failure as mine actually. These belts don't just fail on their own, almost always they get jammed by the pulley or slip due to control problems. But the weak point is the oil pump flow valve. In the video he simply replaces the oil pump with another OEM rebuild. This is actually a really BIG mistake as it will fail certainly fail again. Sonnax offer pump flow control upgrades for the JF011E which also fit the JF016E. I have their valve installed in a brand new Jatco oil pump, which is the best way to go.

For those that don't know, the JF016E can utilize the heavier duty 901074 (D822700) pushbelt rated for +400 N-m, though the transmission typically comes with the lower rated 901089 belt, not sure why that is. This is the highest rated push-belt used by Bosch (see attached specs). Anything stronger Jatco use the "Luk" chain instead such as the Nissan Maxima on the JF018E.

Other improvements mentioned in the video @ 17:25 he talks about are the revised factory "roller pin" for the pulley sheaves that replace the 6mm roller bearings in the older JF011E that are known to fail. The forward clutch drum is still a 3-disc clutch with the smaller spline hub, so that still has a torque limitation. So the JF016E has some nice updates but a few areas that could be improved upon. The main critical differences are: 1) New pulley has smaller shaft diameter for new pushbelt clearance and smaller running ratio 2) Pulley's can close tighter to grip the narrower 28mm belt 3) New pulley use a stronger "slider pin" vs. "6mm ball bearings" for pulley sheave axial translation.

The final picture is the difference between the JF011E (RE0F10A/B) to the JF016E( RE0F10D) pushbelts. Along with some technical data on the 28/12 belt design which makes it so much improved over the existing 30/10 and 30/12 belts. The chain belt is used on the heavier duty JF017E.

The remaining pictures compare the JF011E pulley system to the JF016E from the WIT CVT catalog. The JF016E pulley case (i.e. pulley, belts, etc.) for the Nissan Altima is P/N 31209-28X9A for about $995 brand new, though it looks like they may have discontinued it recently. From the diagrams it looks like there is a strong possibility the pulleys would swap in. The bearings shown would also need to be run to make it fit properly, along with a provision for a speed sensor reluctor which the new pulley doesn't have. That would require some custom machine work but it wouldn't be a structural component, just a speed sensor pickup. This is in addition to the stronger 901074 belt which is the main reason to do the swap.

Anyway, throwing it out there to give an idea what the common failure modes are on these CVT and what might be possible to improve things.

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Discussion Starter #343 (Edited)
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Discussion Starter #344
Figured I'd throw this out there.

The 2015 Juke RS AWD come with a Gen1 motor and a Gen 2 transmission (JF016E). The transmission with upgrade potential, as already mentioned, is the JF016E since it comes with a much improved valvebody and potential to straight drop-in the 901074 (belt, 400 N-m) rated, among many other smaller changes. All other areas can be upgraded to handle more torque as my build thread goes into detail about.

Technically, the AWD JF016E CVT installed onto a Gen1 car with the RS ECM, TCM, BCM, paddle shifters, and transfer case at the very least would make it work, in theory. Unfortunately, Nissan have discontinued the AWD JF016E for some bizarre reason, but the FWD version is still available and so are the Gen 1 JF011E (RE0F10B) transmissions. A FWD JF016E would allow a brand new core for an AWD JF016E transmission rebuild, with only the transmission case, differential, output gear the only likely items needing to be reused. On my CVT rebuild, I took high quality refurbished FWD Altima REF010A transmission parts to rebuild my AWD Juke RE0F10B transmission and everything dropped straight in. Gen2 AWD owners need to realize if they burn up a transmission, they may be out of luck as Nissan are discontinuing quite a few P/N and the trend will only increase.

Too bad Nissan discontinued the AWD JF016E cause I'd have liked to take a crack at upgrading it and doing a Gen2 trans swap.
 

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So what happens if you smoke your Nismo RS Gen 2 CVT in an AWD Juke ?
 

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Discussion Starter #346
Good questions. Yeah, any Gen 2 AWD CVT owners are screwed. They can buy a FWD Gen2 trans which is still available and use it to build a Gen 2 AWD. I could do it, or any transmission shop that knows CVT. It'd be about as good as a brand new unit, cause the entire guts would be transferred over other than the aluminum case and differential. If they did do that, I'd recommend buying the 901074 pushbelt then they have a heavy duty transmission. Throwing it out there for the Gen2 guys who still want support after the factory discontinued parts. Us Gen1 are still good for now. My CVT build was done mainly to be independent from Nissan as much as possible.
 

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Discussion Starter #347
Haven't forgotten about this thread.

I sent out to 3D Systems an RFQ for the forward clutch hub reinforcement last week. They are quoting about $225 plus shipping for a 4140 alloy and 10 business day lead-time. This is the cheapest/simplest solution to the drum strength problem.

I went back and forth on this upgrade. A stronger/reliable CVT transmission cannot be made without it, so I'm just going to do it. To recap: this drum insert upgrade will potentially increase the strength by about + 60-70%. Doesn't sound like a big difference, but the life span will increase significantly. The stock drum might see 30,000 cycles @ 257 lb-ft based on my FEA analysis, whereas with this upgrade would increase that to about 4,000,000 cycles @ 257 lb-ft. There are some potential weak-points in the spider gear assembly that sits within the drum, but I didn't see much wear or abuse so I'd say they should hold up with proper driving/tuning. As I've mentioned before, when this part goes, it trashes the input shaft, the stator housing, and a few more expensive parts. The BOSCH pushbelt will then depend on the improved traction from the AMSOIL CVT fluid to keep it from shredding apart under high torque, along with the improved cooling system I plan on running.

Originally I was going to high temperature solder the hub insert in place, but this would then require heating and removing the torrington bearing I red-loctited behind the drum. Since I have to take the forward drum out anyway for the oil pump upgrade/replacement, this hub reinforcement insert will simply by JB welded into position or possibly I'll use Loctite Bearing retainer compound. It'll be a hand honed slip fitment with some grooves filed in to allow the adhesive to bond the parts together. The main concept here is to have "zero" gap between the insert and hub, such that any stress loads are directly transferred thru the reinforcement to share the load. Then in the hollow primary input shaft I will custom cut the tapered cavity bigger for the reinforcement piece to sit it using a carbide valve cutter with 80* angle, as the picture cross section shows.

At this point, this would then conclude basically everything I would do to the CVT transmission. Hopefully within the next month I can get everything back and fitted up so I can wrap up the transmission.



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Ok so I know I asked this before. What are your top must have upgrades for the CVT? I’m just thinking of breaking it down in order of most effective to “bonus upgrade” or best bang for your buck. I’ve seen you talk about valve body upgrades, push belt upgrade with pulley changes, clutch drum upgrade/insert and I’m sure there are others.

I want to keep my juke as long as I can and I know at some point the CVT will go (though I’m doing everything I can to prolong it). So when it does go, I will want to do a tear down analysis and upgrade.
 

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Discussion Starter #349
Squirtbrnr, good question.

The main problems are Valvebody and Oil pump relief valve.....they quickly destroy the CVT belt if they wear out. They wear out because the CVT oil get's contaminated. That low CVT oil fluid from the factory probably did more damage to my CVT then anything else, so checking fluid levels religiously is another one. I then had a sneaky CVT oil leak later on around 60k miles that I didn't catch right away, which IMHO did some more damage. Thus, the AMSOIL CVT fluid changed/checke often and a CVT cooler are must haves if you can do it early enough. I don't know your mileage but I think if you can catch it early you can extend the life a bit. I know these seem basic, but they are the root cause as to the why of what happened, at least in my case.

If you are willing to upgrade/rebuild, then options become available to actually have a nice reinforced unit. I'm on the fence about recommending rebuilding a stock CVT with any serious mileage. I did it to prove a point to myself, but the deeper I went into the build I started realizing how much labor and money it took to recondition the transmission. Once I get my car running I'll come back and maybe write a FAQ or something in .pdf that'll help out with a rebuild if anyone is brave enough to try it.

I'm recommending to anyone to simply buy a new CVT transmission, then if you want to carefully teardown and rebuild it, that is the way to go. The factory made about 5-6 critical mistakes in the Juke CVT design, but IMHO I think they can be corrected as I've attempted to illustrate in this thread. Enough anyway that you can drive it like it's meant to even with some mods. If I didn't believe it was worth it I wouldn't have done it. It's about keeping realistic goals with the car.

Top upgrades:

-New Nissan Valve body replacement @ 60,000 miles: Must
-AMSOIL CVT fluid changed often: Must
-External oil cooler: Must
-Sonnax Oil pump relief valve w/new Jatco oil pump replacement: Must (not easy to install)
-4th clutch disc added: Must (custom machine work)

-Bosch CVT pushbelt (latest SKU 901083 that replaces stock 901066) : Nice to have
-SAP Pulley ball bearing to slide pin conversion: Nice to have
-Forward drum hub reinforcement insert: Nice to have
-SAP Bonded pistons (for forward/rear clutch): Nice to have
 

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Great! Thanks for that. I’m on 84k miles all done by me. 2 fluid exchange by a dealer (45k and 75k). The next will probably be at 100k and I’ll make the switch to AMSOIL after a flush with factory NS-2 first. At that time I will probably drop the pan (replace the gasket too) and I’ll snake a borescope up beyond the valve body to look at the pulley surfaces. Knock on wood, I’ve had no issues. I have some jerking at partial throttle but I think it’s tune related because under stock tune I don’t have the issue.
 

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Here is a question. The one time my CVT overheated, I checked the fluid, and it was full of bubbles. The fill was slightly on the high side. I think on the long, uphill mountain pass in 100+degree weather going 80+, the fluid expanded and started to aerate. Obviously, gas is compressible and potentially would not maintain pully pressure, leading to slippage, etc.

I immediately changed the fluid after than and filled to the mid point, and problem has not returned.

How would you go about trying to ensure fluid aeration doesn't happen? Any potential mods to address it?
 

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Discussion Starter #352
Ine937s,

It shouldn't aerate if it's filled properly or the cooling is good. If it's overfilled it aerates because of the belt whipping up the sump oil. If it's underfilled the oil pump pickups up air pockets, then cavitates, loses belt pressure, and also the oil foams up. Fill it correctly, it doesn't do this. No mods will help here, this is why the oil level should be dead on perfect between the hot/cold lines on the dip stick. When it's done right, it doesn't slip, overheat, or even make noise. I thought about improved oil cooling internally, and the level of R&D wasn't worth it as I'd had to add more oil injectors and also modify the internal oil lube feed circuit to boost the pressure which is around 60-90 psi or so.
 
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