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I now own a ’08 Jeep Patriot Sport, 2.0L I-4 engine, front wheel drive and CVT. It became mine after the previous owner was unable/unwilling to pay for towing & repair from a light front end collision (gotta love mechanic’s lien’s). I don’t know what or how to check/maintain/service the CVT transmission? Jeep forums haven’t enlightened me much so being a ETCG follower, I thought I’d ask the experts here. Thanks for the forthcoming responses.
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I never owned one and I’m no expert. However a CVT is just an automatic transmission that contains a variator. So, I’d treat it like an automatic.
the main thing I see against being able to treat it the same as an automatic is there’s no dipstick to check the level. My interpretation of CVT is that it’d be real similar to the CVT belt driven transmission on an ATV or side by side off road vehicle. Thus making it very finicky, hard to adjust, and worthless if any moisture gets in, on, or around the belt.
That CVT takes Mopar CVTF+4 fliud, do not use anything else. You can do just a fluid service, which is a double drain and fill. The tranny pan has a drain plug in it for this. You drain+fill it with 6.5 qts, then run it on a lift/drive it at all speeds for a minute or two, then drain+fill it again. You can also pull the pan and change pickup filter/clean the pan out as part of the second drain+fill if you want to be very through. Those transmissions have a known issue with pulley bearings wearing out prematurely and getting noisy. Fluid maintenance is the only thing you can do to make it last. If the wrong fluid goes into it and that CVT belt slips just once, it’s over.
The dipstick is a special tool the dealer has, that you may be able to buy yourself somewhere. It’s called a 9336A. Chrysler and Nissan have been trying to copy Benz lately with this no dipstick thing to try and stop lube joints from screwing these things up.
I had wondered about capacity and type of fluid. She’s got 122K miles on now so I’m betting it’d be good to freshen that tranny up. Don’t know if it’s ever been done before. Thanks for the part number on the special tool also. Hope I can return the favor sometime.
Sorry for barging in, but all this made me feel so good about my Camry Hybrid CVT. Best device (not really a transmission) I ever witnessed. Along with lifetime fluid. Does nothing but splash lubricates moving parts.
In order to check the fluid level you need two things: 1- the graduated dipstick Mopar part #9336. Dorman also makes one, part #917-327 as does Miller and 2- temp chart. I will post links below.
With the hood open and looking down in the engine bay, their is a flat area towards the bottom front left of the cvt with a black plug near where the torque converter housing is. This is where you place the dipstick. You need to insert the dipstick into the hole and then use the graduated mm marks along with the temperature chart to get the proper level. According to Chrysler, a scan tool is needed to get an accurate temp reading in order to have an accurate fluid level reading. The fluid you will use is Mopar CVT+4, about $18/qt @ dealership/$8 on Amazon. They also sell it in 5 qt jugs. This CVT is made by Jatco and is used in Nissans. The use of standard atf, even a small amount WILL DESTROY these units!
“Checking the fluid in the CVT
isn’t straightforward. In fact, the procedure
follows along the same lines
as the NAG (722.6) and even the new
62TE. There’s no dipstick; customers
are encouraged to take their vehicle to
a repair facility every 15,000 miles to
have a trained technician check their
fluid. A special tool, Miller part number
9336, is used to check the level, which
depends on fluid temperature. Since the
fluid level can change almost 12mm
from 70ºF to 190ºF, the level must be
checked with the 9336 dipstick and
cross-referenced to a chart or table.
From the bottom of the internal stop the
fluid level should be:
Temperature High Low
77ºF 38mm 25mm
138ºF 42mm 29mm
191ºF 46mm 34mm
The fluid is expected to last the life
of the vehicle, but maintenance schedule
B (which pertains to most vehicles)
would require the fluid to be changed
every 60,000 miles. According to
DaimlerChrysler, schedule B includes
vehicles driven under any of these conditions:
• At temperatures below 32ºF (0ºC).
• Stop and go.
• Extensive engine idling.
• Dusty conditions.
• Short trips of less than 10
miles (16 km).
• More than 50% at sustained
high speeds during hot weather,
above 90ºF (32ºC).”Dorman Dipstick: http://www.dormanproducts.com/gsearch.aspx?type=keyword&origin=keyword&q=cvt+dipstick
Mopar CVT+4: http://www.amazon.com/Genuine-Mopar-Fluid-5191184AA-Transmission/dp/B000TX75GU
Temp Chart: http://etereman.com/blog/fiat-transmission/what-problems-plague-the-chrysler-42lre-transmission (also includes exploded views of the cvt unit)
This will show where the plug is located: http://www.jatco.co.jp/ENGLISH/products/cvt/jf011e.html (It is the black plug by the Torque converter housing that looks like a cigarette lighter.)
Check with your dealership to be sure they didn’t change this through a tsb. I know with the Jatco units found in Chrysler/Nissan/Mitsubishi vehicles they recommend fluid changes every 60,000 miles(severe duty schedule B/100,000 miles schedule A-normal duty) now due to failure from heat. CVT fluid has rubber molecules added to it in order for the steel belt to “grab” onto the clutches. It is a similar set-up to what is used on snowmobiles. Although they do have gears for reverse only. But due to the overheating of the fluid, the rubber melts causing complete fluid break down therefore causing the unit to self destruct. My mother’s 2008 Jeep Patriot has already had one unit replaced after the second overheat condition. It was claimed to be “lubed for life/lifetime fluid”. There is now a TSB on those units about routine fluid changes. Cheers!
[quote=”JC822″ post=128966]….. in order for the steel belt to “grab” onto the clutches.[/quote]
This isn’t quite accurate, it’s actually a lot less forgiving than that.. It’s a full metal-to-metal contact between the belt and the pulleys. I’ve been to manufacturer training on these units and had them apart there and in the shop on live jobs where we are just now being able to service worn out pulley bearings. The metal-to-metal contact is why the right fluid must be used. If that belt slips just once, the galling between metal surfaces ruins it immediately. the pulleys have to be perfectly smooth to work right. It looks like this:
That is the way the dealer explained it to me when I was rebuilding one in my aunt’s ’08 Dodge Caliber last summer. They said that the rubber added cushioning between the belt and pulleys along with the ability to prevent slipping of the belt on the pulleys. That is why I stated grab in quotation marks. If I am incorrect about this then please inform me so I have the correct knowledge on the matter. 🙂
I have to say that you’ve really peaked my interest with this “rubber molecules” in the fluid thing. What I was correcting you on before is the grabbing the clutches, showing that the belt grabs directly on the metal pulley. I don’t believe there are rubber molecules in there, but I’m not willing to tell anyone that there aren’t either. I’ve been researching and found that in general, nobody seems to want to specify the actual chemicals in their CVT fluid additive packages. They will only say the types of chemicals.
One thing I found is this very technical paper which says Zinc dithiophosphate (ZnDTP) is an additive used to improve metal-to-metal friction coefficient. I go back to training in a few weeks and the instructor is a transmission guru at heart. I will ask him about the composition of CVT fluid and rubber molecules and he will probably know for sure about it. The guy is a genius and has incredible transmission industry insider knowledge, he’s a professional networking master. I’m going to keep studying this, though.
When you say you rebuilt one in your aunt’s Caliber, you had it out yourself to fix something? If so, what did you end up doing? I’m curious because I’m not hearing much of anybody opening these things and I’m interested to know whatever anybody is doing with them.
I should point out also that this does not work like a chain between two sprockets where the drive sprocket pulls the chain around the driven sprocket. The drive pulley pushes the belt around the driven pulley. If you examine the design of the belt, you’ll realize that if you were to pull on it with any real force, it would break. The endless stack of metal discs is loose within ribbons of steel that keep them held together and aligned in a straight row. That’s why, in the following picture, there are zip ties holding the belt together. The steel ribbons will just fall right out of the sides of the belt if you don’t hold them in, letting all the discs fall all over the place loose. Installed, they pulleys inherently do the job of holding the belt together.
P.S. I hope the op doesn’t mind that this has gone way beyond the scope of the original question posted.
I’m more than good with the extra info. I’m the type of person that if I make an investment into something, I’m going to attempt to understand everything about it that I can. Thanks for all the good tips & tricks. Looking forward to educating myself more
Hello fopeano,
I was doing allot of research myself about these units. I have read in many Nissan/Infiniti and Jeep/Dodge forums about these CVT units. Many people have said (including the one tech at my local dealership) that it does contain rubber molecules as a friction modifier/belt protectant. Of course I went with what a Chrysler Tech had stated which was then confirmed through research on forums. It was also stated that the one clutch is a variable geometry pulley type that actually increases in size as the speed increases to make it feel like it is shifting gears. Now I am not 100% positive about that but it is been mentioned on numerous occasions in the Jeep Patriot forums as well as Dodge Caliber and Nissan forums. I am just trying to learn as much about these units as possible and am open to any information others can educate me on. I know they are much easier then the standard transmissions to work on. And they are very similar to the way a snowmobiles clutch is set-up ecept for the steel belt versus a rubber belt. As I have stated, I rebuilt (actually helped; my cousin and I did it) the CVT in my aunt’s Dodge Caliber due to the belt breaking. Unfortunately she did not have the lifetime warranty as it was purchased secondhand. I will add some links to different information I have also found and what has been stated in forums. Maybe you could culminate all this information and ask the instructor you speak of. I do agree it seems they are being very tight lipped about these units fluids composition. I do want to posses as much knowledge on these units as possible considering there are two Chrysler Jatco’s in my families vehicle list. There are 3 types of cvt’s: Hydraulic, mechanical, and electrical. The Jatco’s are hydraulic if I remember correctly. 🙂
I also know these units can have up to 1000 psi while in operation. So making sure the knowledge possesed on these units is critical. That is why they have the fluid formulated the way they do.
Links for your reading pleasure:
http://forums.nicoclub.com/cvt-tranny-with-no-dipstick-t294397.html (rubber mentioned in fluid)
http://www.google.com/patents/US20130065802
http://www.hindawi.com/journals/at/2012/476028/ (“In Figure 4, the CVT has higher efficiency at lower speed, lower CVT ratio, and medium torque. to represent distributed CVT ratios 0.5 to 2.5. The efficiency at any ratio in between is obtained by using linear interpolation. The efficiency of a steel-belt CVT with special oil containing rubber molecules to lock the belt with the pulley can reach up to 97%, similar to that of a manual transmission [4].”)
http://www.hi-tecoils.com.au/wp-content/uploads/2012/12/Honda_CVT_Transmission_Fluid_Nov17.pdf
http://www.scientific.net/AMR.915-916.183
http://theanxiousthoughts.blogspot.com/2013/12/the-technical-side-of-continuously.html
http://www.caliberforumz.com/archive/index.php/t-24795.html (micro pellets of rubber discussed)
http://www.nissanmurano.org/forums/61-general-discussions/1540-cvt-operating-charactistics-print.html (rubber molecules mentioned)
http://forum.autoworld.com.my/index.php?showtopic=71827&st=10 (rubber molecules discussed; “To smoothen the transmission, a special CVT fluid is needed, that which contains rubber molecules. It is these rubber molecules that protect the CVT against premature CVT heaven. I initially also thought that the CVT belt was made of rubber but was corrected by one of
my well-informed City club members.” Talking about racing cvt’s)http://www.engineerlive.com/content/20649 (“For automotive applications, DAF was the first manufacturer to make a real success of CVT technology in the late 1950s, with its small passenger car that utilised the company’s Variomatic CVT. This transmission was based on a rubber belt running between variable diameter pulleys. CVTs with more robust steel belts have subsequently been used in vehicles such as the Ford Fiesta and Fiat Uno. Other automotive manufacturers that have launched models with a CVT of one type or another include Subaru, Nissan, Honda, Audi and BMW.” “Another area of interest currently lies in the Formula 1 (F1) race car industry. Perhaps unusually, the CVT-related technologies being developed by F1 teams have the potential to be rolled out into production vehicles relatively quickly. Formula 1’s governing body, FIA (Federation International de l’Automobile), has decreed that from the start of the 2009 season teams will be permitted to use kinetic energy recovery systems (KERS) for the first time. And one way to implement a KERS system is to connect a flywheel-based energy storage unit via a CVT, as is the case with the system being developed by transmission specialist Xtrac. The Xtrac system utilises a Torotrak full-toroidal traction-drive infinitely variable transmission (IVT) technology, which is a variation on the CVT concept.” )
http://www.gulf.nl/fileadmin/user_upload/sheets_EN/03_transmission/safety/2455%20Gulf%20CVT%20Fluid.pdf (Even the SD sheets fail to mention the actual composition of the fluid.)
http://www.amsoil.com/msds/CVT.pdf
And yes, I think we did hi-jack the op’s thread! :silly: BUT if it can help people with their vehicles I hope the OP doesn’t mind. SInce these units are being increasingly more common in modern vehicles any and all information we have is only a benefit for us, not a detriment.
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