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Improved CVT Performance

4K views 6 replies 3 participants last post by  RonD 
#1 · (Edited)
I posted elsewhere about changing my CVT fluid and CT cooler filter. I bought the 2008 Patriot with 142k miles on it. A service record reported the fluid and mesh filter above the transmission pan had been changed at approximately 122k miles, yet the CVT was seriously whining during warmer weather, and I had a few codes, including the CEL once. I swapped out the fluid and cooler filter at 144k.

I don't hear the whine any longer and the transmission seems to change the gear ratios continuously and smoothly. I believe this is how a CVT operates and any felt shifting is under rapid acceleration (downshifting) at higher speeds. I have also noticed that I now have a pronounced engine slowing as if drag is exerted by the CVT when I decelerate. This was not pronounced prior to the service. I read on these posts that folks feel a sensation of engine braking with the CVT's. Does any one know if this is engine braking or drag created by CVT? It is quite real and I feel as if this is more than engine fuel cutoff. I am curious.

I am also wondering that since I had to disconnect the battery cables, could this change my computerized driving style and create more drag from the CVT or engage the fuel cutoff sooner?

One last question - Has anyone replaced the valve cooler bypass? It feels to me that one of the "through lines" from beehive cooler is not as warm as the other lines. I wonder if the valve could be partially stuck closed or open. For $40 - $50, I could probably replace this before messing around with a external cooler pressure check.

I appreciate all of your collective experience and thoughts. Thanks.
 
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#3 · (Edited)
I posted elsewhere about changing my CVT fluid and CT cooler filter. I bought the 2008 Patriot with 142k miles on it. A service record reported the fluid and mesh filter above the transmission pan had been changed at approximately 122k miles, yet the CVT was seriously whining during warmer weather, and I had a few codes, including the CEL once. I swapped out the fluid and cooler filter at 144k. I don't hear the whine any longer and the transmission seems to change the gear ratios continuously and smoothly. I believe this is how a CVT operates and any felt shifting is under rapid acceleration (downshifting) at higher speeds.
This is why I sometimes ask posters that are having problems if they know whether a change has been done and how long ago, as a change may (though not always) fix the problem even if the CVT is throwing codes and seems as though it's truly gone bad.

Don't count 'em out too early! :)


I have also noticed that I now have a pronounced engine slowing as if drag is exerted by the CVT when I decelerate. This was not pronounced prior to the service. I read on these posts that folks feel a sensation of engine braking with the CVT's. Does any one know if this is engine braking or drag created by CVT?
I'm not sure why exactly, but if it helps mine has always done that since new.

I am also wondering that since I had to disconnect the battery cables, could this change my computerized driving style and create more drag from the CVT or engage the fuel cutoff sooner?
Possibly, yes.

One last question - Has anyone replaced the valve cooler bypass? It feels to me that one of the "through lines" from beehive cooler is not as warm as the other lines. I wonder if the valve could be partially stuck closed or open. For $40 - $50, I could probably replace this before messing around with a external cooler pressure check.
I haven't yet, but I do recall others here having to replace them because they weren't opening when they should.

As a side note, I've thought about replacing the beehive/soup can and cooler bypass valve on mine with the integrated bypass valve plate and associated tubing. The beehive is like a mini radiator and can restrict flow if it gets clogged with sludge. The other problem, though rare is that they can develop leaks that allow engine coolant into the trans and ruins it.
 
#4 ·
Thank you Sandstone,

Is the bypass cooler plate assembly similar to what is used by Mitsubishi?

Given what I paid for this Patriot, I am more than willing to replace a few components, or have them on hand if they have a history of failure. I live in Southern Oregon and drive a lot of back roads and high-clearance tracks to get to trailheads in the Trinity Alps, Russian Wilderness, and Marble Mountain wilderness of Northern California. I would hate to get stuck somewhere with an older vehicle I have little experience with. Although, from the many posts I have read, it seems these Patriots can limp along even when a repair is needed.

I am impressed by the ability to lock down the 4WD. We get a lot snow and slick conditions on the east side of the Cascades, and this Patriot outperformed my 2010 Subaru Forester in off-highway approaches for backcountry ski approaches. I wish I had the ability to over-ride the AWD and lock in 4WD in the Forester.
 
#5 · (Edited)
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