The Nissan Path

I just bought a used 06 nissan Pathfinder (love it!) and it had the
dreaded shudder from the initial test drive and after a transmission replacement.

I drove all this weekend (after finally getting it back from my dealer on this past Friday) in 2WD mode with just a hiccup here and there..

usually it would shudder around 55-65 mph when lightly accelerating.. Not sure what that's about.. Also shudders at slower speeds when I set the selector to Auto.

anyone have suggestions? I'm having them check the fluids today

I am sorry I caught this post so late...

Did they replace the radiator when they replaced the transmission?

The only thing (within reason) that generally kills these transmissions is a failing radiator mixing coolant into the ATF via the heat exchanger built into the radiator.
Your model year is infamous for it.

Putting in a new transmission without replacing the radiator simply will destroy the new transmission.
If you paid a shop to replace the tranny they must have the professional knowledge to replace the raditor or at the very least bypass the ATF loop from the radiator.

Any aftermarket radiator as well as the newer OEMs radiators will not have this issue.
It was specific for the radiators put into the 05-10 model years with the 05+06 being the most vulnerable.

You might have simply gotten a bad transmission. What kind of transmission was it...used, Nissan reman or aftermarket reman? Is it a Nissan dealer that did the work? Palmerwind makes a good point in regards to the radiator, although in some cases they might use Kooler Kleaner to backflush the trans cooler in the radiator if the radiator had already been replaced or wasn't the cause of the initial failure. A bad U-joint could cause vibration, but I would hope they would have noticed this when the replaced the transmission. Let us know how you make out!

Sorry to bring up an old thread.

Not sure if I have the same issue as OP. Had the tranny replaced some weeks ago due to a "no reverse" issue. Mechanic suggested replacing the entire tranny as messing with the valve body would be more time consuming and also due to unavailability of replacement parts.

Got a surplus/used tranny mounted and all servicing done. BTW, the radiator was replaced (new) when I bought the Pathy (used) back in 2019.

Pathy runs fine although there are times when it seems to shudder/kick even when on cruising speed - doesn't matter what speed. It feels like when someone kicks your chair from behind and I can hear my rear diff seem to "thud" as if it's slamming.

Had to ease off the accelerator and slowly speed up again to get out of that "kicking".

Still trying to figure out where/how it's doing it, so any ideas/suggestions is highly appreciated.

1st things first.

your surplus transmission, but you did not state which torque converter was used.
old one, the surplus one that came with the transmission you had installed, or a new remanufactured one.

the surplus transmission, came from which vehicle? Another 06?

that kicking occurs between 30-45 mph, around 1000-1200 rpm with light pedal applied while coasting?
You let off the pedal to stop the kicking, to get it some gas to get out of that "zone" and eliminate the vibration?

Sorry, wasn't entirely clear on the tranny.

Not particularly sure on the torque converter as the surplus tranny was purchased as a whole assembly. Safest guess would be torque converter came with it.

No info on what year model it came from to be honest, but from what I see so far, it matches the previously installed one in mine (07 Pathy btw).

No particular speed, however it does mostly occur starting from around 80kph, more or less, and I do have the accelerator lightly pressed to keep speed. Once the kicking/bucking starts, I let go of the gas to stop it; then slightly depress to gain speed again (with the kicking gone).

I'm in talks with my mechanic who worked on it to have him recheck. Would be having a test drive by next week with him so he has an idea what I'm experiencing.

Hmmm.

shuddering usually is the torque converter.
Installing an old torque converter, is tricky.

A scan tool, looking at the solenoids and control from the TCC, may show how they are shifting, and when the shuddering occurs. Not sure what data and bi-directional control we have on the 07, might be just monitoring.

Nice video here by Pine Hollow dude that tested it for a customer on a GM product. Symptoms are very similar? Have a look, maybe it matches up.

https://www.youtube.com/watch?v=Q4PFHMq ... iagnostics

Can't say I have the same issue as per PineHollow. Can't hear the "thud" I get when it happens.

And since you've mentioned RPM, I paid attention to mine when I was driving.

I get that shudder/bucking when my RPM seem to "stick" anywhere between 1300 - 1800 - mostly around 1500 - and when applying gas does not immediately make it climb. I see minuscule increase in RPM even when applying the same amount of pressure on the gas pedal usually revs it past 2000 immediately.

Also, it does not get past 2500 when in gear; although it climbs over 3000 when in neutral. I've read somewhere that this means it's on limp mode. However, my speed climbs to 100kph and no SES/CEL.

I think you are at the point where the mechanic is going to have a deep dive into it for sure.

Hope you let us know what they may find!