Vibration in Auto mode (4WD system)

[McFalconPunch]

My 2003 Pathfinder has the electronic 4wd selector (2WD, Auto, 4Hi and 4Lo). Ive read through about 2 hours of posts searching and I cannot find this exact issue. I've only owned my Pathfinder for a month so I've always been in Auto mode. Heres of list of things I have done either chasing this issue or just replaced because it was worn:

Front wheel bearings changed
4 new tires
Front & Rear brakes
ball joints
sway bar end links
Differential oil
Transmission Fluid
Greased rear driveshaft


Anyways, the vibration is between 30-80mph, 60mph being the worst. Just for S&G's I switched it to 2WD mode at 60mph. The vibration went away, also throughout that range. The pathfinder drives smooth as butter. I have not changed the transfer case fluid yet because I need to buy more ATF.

What other things should I be looking out for? Seems like an odd issue that literally goes away with the turn of a switch.

[Hawairish]

Front driveshaft can be a culprit for vibrations in general...but not really in the scenario you described by switching to 2WD. For all switch settings, your front driveshaft is spinning, so I'd expect the vibrations to be constant. Might need to browse the FSM for a system description and determine exactly what the t-case does for each switch scenario to see if you can rule anything out.

[Brian VT]

Yup. Transfer case seems the likely culprit.

[atraudes]

I've seen a couple of threads on the topic but as I recall, there was never a single solid solution. I have the problem myself, but the vibration's very subtle so I haven't put too much energy into it. The best recommendation I can give is to change the diff and transfer case fluids if you haven't already, and be sure to use the right weight and use LSD if you need it (there should be an orange sticker on the diff saying "LSD only" if you need it; you probably do).

Here's the threads that I was able to recall, maybe they'll help or at least get you started.

2001-qx4-vibration-transfer-case-t597562-30.html
the-feel-of-four-wheels-t605487.html
4-wheel-mode-selector-on-or-off-t605194.html

[McFalconPunch]

Thanks everyone. I was under the assumption that in Auto, you'll only be in 4wd if the ABS system detects slippage, so that's why I never messed with the switch. I looked through the FSM and didn't see anything that would likely cause this issue. Ill probably just keep it in 2wd until I actually need to be in 4wd. The only time I currently need 4wd are when I go check my gas wells, and those are on 2 tire track paths well below the speeds where the vibration happens at.

The transfer case is the only fluid I haven't changed yet, I might start with that then change the front u-joints. If that doesn't fix it then I will just live with it.

[McFalconPunch]

problem-with-auto-4wd-t309582.html

Another with the same issue, no solution :P

[rgk]

I had the same issue. Two things brought the vibration down by about 90%: I changed my diff fluid, and I rotated my front driveshaft 180 degrees. This made such a noticeable difference that I am convinced a different driveshaft would cure the issue.

My vibration is most pronounced at 45 mph in 2wd, and about 60 mph in AUTO. When I switch from 2wd to auto and vice-versa, the vibration goes away or gets worse, depending on my speed. Probably the driveshaft is creating some sort of weird harmonics.

And the car does feel as if some power is transferred to the front driveshaft in AUTO, even if no slippage is detected.

[barnaclebob]

I have the same issue if I leave it in Auto. I'll get vibrations above about 50mph and when i switch it to 2wd i get a bit of a clunk and no vibrations. I'm pretty sure when I put it in auto its always in 4wd. I'll also get horrible gas mileage in auto because I think its in 4wd. Its not really big enough of an issue for me to fix. I've always driven in 2wd unless on snow or needing to accelerate hard on wet roads.

[McFalconPunch]

I tried to replace my transfer case fluid but the fill bolt didn't want to budge. Did check the front driveshaft and the u-joints are good and there is no play. This will probably have to wait until I make another trip to Harbor Freight to get a breaker bar.

[yeldogt]

It should not be changing Auto vs 2wd -- you are correct .... it's only going to go into 4wd if for some reason the wheel sensors detect a slip. You have replaced all your tires -- all the same correct? Auto is really just the "on" position for the system.

I'm thinking maybe the transfer case is somehow malfunctioning. I don't know the exact workings of the transfer case -- my memory is that it requires the movement of the drive shaft to maintain pressure -- so it must have conventional auto clutch and maybe converter. I would change out the fluid -- make sure to use the proper D Matic fluid vs a generic. My memory is that 6 quarts does both a simple dump/ fill of the transmission and the transfer case -- I think the transfer is only about 1.4q. The slightly higher cost from Nissan is minor -- and it will have all the correct additives vs stock Dex.

[atraudes]

I tried to replace my transfer case fluid but the fill bolt didn't want to budge. Did check the front driveshaft and the u-joints are good and there is no play. This will probably have to wait until I make another trip to Harbor Freight to get a breaker bar.

Yeah mine were insanely hard to get off too. I think there may have been some sort of threadlocker (maybe just a sealant?) on the plugs. I remember having my feet on the longest wrench I could fit under there and pushing against the running boards to get it broken loose. I highly recommend getting a proper square head socket instead of using a 3/8" ratchet extension. The extension is slightly smaller than the plug so you run a higher risk of stripping it out, especially with how much force is required in this case. The square head socket will fill the plug more precisely. They can also be used for the front and rear diffs.

[McFalconPunch]

Update:
I finally got around to changing out the transfer case fluid. When I removed the fill plug, it drained out like it was coming out the drain plug, so it leads me to believe that the fluid has never been changed in its 154k miles of existence. It was really dark purple color, almost black. I got about 1.5 qts back in it. I will change it again in a week or so and keep doing that until the fluid comes out nice and red.