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Discussion Starter · #1 ·
Just got home from my morning with the specialist Nissan NA flew in to inspect/repair my PF. We were able to make our PF shudder 3 times while hooked up to his software. We asked him questions for over 2 hours, but I will post what I found most interesting.

There are 3 different judders:

DRONE judder, which is normal. This is known by the low drone like noise that your PF does when first accelerating - when it is searching for the correct ratio to go into. The specialist said that lots of PF owners are bringing theirs in with only the drone judder, but don't understand the judder enough to know their PF isn't affected by the 2 more serious judders.

TORQUE CONVERTER judder. This judder can be verified by hooking up to the software, and can be fixed by simply putting in another torque converter. He said Nissan has had great success with fixing this type of judder for customers.

PRESSURE judder. This one is more problematic for Nissan. This can also be verified by hooking the PF up to the Nissan software. He said that at this time, Nissan doesn't have a guaranteed fix for this judder. Their only solution is another new CVT and torque converter.

He did verify that Nissan has made a redesigned CVT, and this is what will be put into our PF. He does not know when it will be available for installation. He assured me that it had been properly tested, and would not affect gas mileage or reliability.

Carrie
 

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WOW, great news. I am getting so frustrated. After the new TQ install, the shudder is prevalent under 20mph v over 20mph.
I am looking at the new Acura MDX, but not looking forward to losing $$.
 

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Mine started juddering yesterday it's horrible I couldn't drive it at lower or higher speeds it was basically if I feathered the gas rather than flooring it it would 100% guaranteed buck like a bronco. Very concerning I just kept coasting and accelerating, coasting, accelerating to get home. I'm making an appointment to get it checked out. I fear that I'm also going to be screwed. I wish that I had noticed this problem before I bought the vehicle and I would have avoided it.
 

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Mine started juddering yesterday it's horrible I couldn't drive it at lower or higher speeds it was basically if I feathered the gas rather than flooring it it would 100% guaranteed buck like a bronco. Very concerning I just kept coasting and accelerating, coasting, accelerating to get home. I'm making an appointment to get it checked out. I fear that I'm also going to be screwed. I wish that I had noticed this problem before I bought the vehicle and I would have avoided it.
What you're describing is not what most people are referring to when they talk about the "judder" or "shudder". That problem is far more severe and is likely some other defect in the drivetrain. The shudder typically happens at low speeds and light throttle - and when it happens, it can be negated by either adding or decreasing throttle, which makes it go away instantly.

It's important to understand the distinction because the waters are muddy enough when it comes to this problem. Please don't mistake this for my being unsympathetic toward your issue, I'm just trying to provide clarification so that you can get your problem addressed appropriately. If you go in complaining that you have the infamous "judder" or "shudder", there is a very sharply defined diagnostic protocol at this time - but your issue is not the same thing and you want to avoid going down that path and allow the tech to diagnose the issue, rather than reaching a foregone conclusion.
 

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Maybe I'm not good at describing it. That's what I meant by feathering it. Between like 20 and 50 mph if I lightly accelerate the the vehicle shakes and slams like something is loose or jerking. Maybe it's not the same thing but it seems like what everyone is describing.
 

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Maybe I'm not good at describing it. That's what I meant by feathering it. Between like 20 and 50 mph if I lightly accelerate the the vehicle shakes and slams like something is loose or jerking. Maybe it's not the same thing but it seems like what everyone is describing.
The shudder is typically an intermittent thing, at low speeds (below 30MPH) and usually during a turn. If you had to coast/accelerate hard the entire way home to avoid it, then I'm not sure you're having what the rest of us are.
 

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this was posted somewhere else. Its still hard to imagine in my head how to tell the difference between the judders..

So the pressure shudder is the one that requires replacing the entire transmission and converter assembly.. And even then there is still a chance you could have the judder.
 

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The shudder is typically an intermittent thing, at low speeds (below 30MPH) and usually during a turn. If you had to coast/accelerate hard the entire way home to avoid it, then I'm not sure you're having what the rest of us are.
the judder has nothing to do with being in a turn...why would you say that? no one is complaining that this happens during a turn and nissan doesn't even have being in a turn as part of their diagnostics. both judders happen within the drivetrain where being in a turn has nothing to do with it.
 

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Just got home from my morning with the specialist Nissan NA flew in to inspect/repair my PF. We were able to make our PF shudder 3 times while hooked up to his software. We asked him questions for over 2 hours, but I will post what I found most interesting.

There are 3 different judders:

DRONE judder, which is normal. This is known by the low drone like noise that your PF does when first accelerating - when it is searching for the correct ratio to go into. The specialist said that lots of PF owners are bringing theirs in with only the drone judder, but don't understand the judder enough to know their PF isn't affected by the 2 more serious judders.

TORQUE CONVERTER judder. This judder can be verified by hooking up to the software, and can be fixed by simply putting in another torque converter. He said Nissan has had great success with fixing this type of judder for customers.

PRESSURE judder. This one is more problematic for Nissan. This can also be verified by hooking the PF up to the Nissan software. He said that at this time, Nissan doesn't have a guaranteed fix for this judder. Their only solution is another new CVT and torque converter.

He did verify that Nissan has made a redesigned CVT, and this is what will be put into our PF. He does not know when it will be available for installation. He assured me that it had been properly tested, and would not affect gas mileage or reliability.

Carrie
This was documented by me in another post and it's clear that it's not as easy as saying "if this, then that". Timing of when you acted on existing TSBs, manufacturing dates, dates of parts, etc. all play a part in the diagnosis. There's a one page flow chart in the TSB that determines what they need to do.
 

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Maybe I'm not good at describing it. That's what I meant by feathering it. Between like 20 and 50 mph if I lightly accelerate the the vehicle shakes and slams like something is loose or jerking. Maybe it's not the same thing but it seems like what everyone is describing.
best description out there is that it feels like you are driving over rumble strips...
 

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DRONE judder, which is normal. This is known by the low drone like noise that your PF does when first accelerating - when it is searching for the correct ratio to go into. The specialist said that lots of PF owners are bringing theirs in with only the drone judder, but don't understand the judder enough to know their PF isn't affected by the 2 more serious judders.
I knew one of them was normal, typical CVT, honestly..
 

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the judder has nothing to do with being in a turn...why would you say that? no one is complaining that this happens during a turn and nissan doesn't even have being in a turn as part of their diagnostics. both judders happen within the drivetrain where being in a turn has nothing to do with it.
Wrong and it does happen often in a turn. I reported this back in Jan and even my dealer experienced it in a turn. It happens to me and even after the torque converter (D) replacement it has occurred again but only in a turn. I understand it's not in the TSB but bottom line it still occurs in a turn and for me this is usually when it is experienced.
 

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Wrong and it does happen often in a turn. I reported this back in Jan and even my dealer experienced it in a turn. It happens to me and even after the torque converter (D) replacement it has occurred again but only in a turn. I understand it's not in the TSB but bottom line it still occurs in a turn and for me this is usually when it is experienced.
Totally agree. And a left turn for me.
Although many factors I've noticed present when it happens.
Left turn
Slight incline
AC on
4 + people in the vehicule
Always happens when engine has warmed up.
 
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the judder has nothing to do with being in a turn...why would you say that? no one is complaining that this happens during a turn and nissan doesn't even have being in a turn as part of their diagnostics. both judders happen within the drivetrain where being in a turn has nothing to do with it.
This is why I used the term "usually" - as in, not "always".

Many of the members reporting the judder have encountered it during a turn, though I'm aware it's not limited to only occurring during turns. It may be entirely coincidence, because turns often happen under light throttle, low speed conditions, similar to the other criteria for the judder.
 

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Discussion Starter · #15 ·
this was posted somewhere else. Its still hard to imagine in my head how to tell the difference between the judders..

So the pressure shudder is the one that requires replacing the entire transmission and converter assembly.. And even then there is still a chance you could have the judder.
The Nissan specialist can tell the difference in the judders by what is shown on his computer screen. He could tell right away that ours was the pressure judder, and not the TC judder.

Yes, the pressure shudder requires replacing the whole CVT, and there is still a chance that the "new" CVT that Nissan gives you may also have the pressure judder. Both of my CVT's have had the pressure judder. The Nissan specialist said that Nissan understands what is happening during the pressure judder, but doesn't quite know how to fix it yet - hence the new CVT.
 

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Discussion Starter · #16 · (Edited)
the judder has nothing to do with being in a turn...why would you say that? no one is complaining that this happens during a turn and nissan doesn't even have being in a turn as part of their diagnostics. both judders happen within the drivetrain where being in a turn has nothing to do with it.

Nissan knows that the judder often occurs when making a left hand turn - the Nissan specialists told us that. It may not be in the TSB, but is well known by Nissan. He told me they can't explain why a turn can cause the judder. The specialist told me that he spends alot of his time trying to replicate the shudder in customer's PFs, and he knows to drive on hills, make left hand turns, drive in stop and go traffic, and slowly accelerate from full stops. Nissan is well aware of which driving conditions can make the PFs shudder
 

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Nissan knows that the judder often occurs when making a left hand turn - the Nissan specialists told us that. It may not be in the TSB, but is well known by Nissan. He told me they can't explain why a turn can cause the judder. The specialist told me that he spends alot of his time trying to replicate the shudder in customer's PFs, and he knows to drive on hills, make left hand turns, drive in stop and go traffic, and slowly accelerate from full stops. Nissan is well aware of which driving conditions can make the PFs shudder
well at least they're onto it, with them already being able to replicate it is a sign this problem could come to an end eventually, hopefully sooner than later.
 

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Nissan knows that the judder often occurs when making a left hand turn - the Nissan specialists told us that. It may not be in the TSB, but is well known by Nissan. He told me they can't explain why a turn can cause the judder....
My research into the design of the CVT8HT clearly shows that they made the transmission fluid pump smaller, and lowered the level of fluid in the transmission. Depending upon the fluid level and the location of the pump pickup point, it could be partially starving on left hand turns when the fluid sloshes right and briefly starves the pump.

Had a previous vehicle with a carb that died on left hand turns because the float in the carb fuel bowl partially sunk, lowered the level of gas in the bowl, and would interrupt gas flow on a left hand turn. Same basic concept. A possibility.
 

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My research into the design of the CVT8HT clearly shows that they made the transmission fluid pump smaller, and lowered the level of fluid in the transmission. Depending upon the fluid level and the location of the pump pickup point, it could be partially starving on left hand turns when the fluid sloshes right and briefly starves the pump.

Had a previous vehicle with a carb that died on left hand turns because the float in the carb fuel bowl partially sunk, lowered the level of gas in the bowl, and would interrupt gas flow on a left hand turn. Same basic concept. A possibility.
Interesting, thinking about it and imagining it, it sure seems like whats happening here. Where were you finding details of the CVT8HT?
 
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