The feel of four wheels

[marioc89]

I'm just realizing that my truck feels like its in 4 wheel drive with the vibration from the axle engagement. Anyone knows what this could be?

[Hawairish]

Thinking you'll need to elaborate on this a lot more if you want a better answer. What are you doing?

[marioc89]

Well, I'm not doing anything but driving it. I know that while driving in 2wd mode it feels more smoothly than driving in 4wd mode. In 4wd mode, I can tell it's engaged by the vibration of the trans axle or drivetrain. Well once I reach higher speeds is only when I feel it just the same with it in 4wd mods. So now, the only time I know its in 4wd mode is by the indicator light on the dash and the thump feel when you put it in park. I hope that was a good enough explanation.

[Hawairish]

Sort of helps. I can infer by your profile you have a QX4, which has the auto-mode 4WD. But some had just a dial, and others had a dial and shift lever.

Which do you have?
Are you putting it in 4WD or AUTO? (The 4wd system engages in either and triggers the indicator light)
What terrain are you driving on, and at what speeds?
When was the last time you check any drivetrain components and transfer case fluids?

[marioc89]

I have a dial. And I'm just driving on the highway, nothing off road. I hadn't checked either. How can I check the transfer case fluid?

[yeldogt]

The truck is not really designed to drive in 4WD on dry pavement. It's not an AWD system .... it's old school 4WD. I believe Nissan says max 50MPH. Also -- the tires need to be all the same (type and tread depth). Different sizes will stress the system -- the tires have to slip on the pavement.

The Auto system in the Pathfinder LE and the QX4 -- is not like AWD. The truck in not in 4WD when the switch is in "Auto" ... the "Auto" position only "allows" the system to engage 4WD using the motorized transfer case. The truck IS in 4WD when you have it on 4WD high or low.

It only goes into 4WD when it notices wheels slipping -- it then engages 4WD. It does not stay in 4WD.

[Hawairish]

Yeldogt hit the nail on the head on all points.

It's in your best interest to read your owners manual.

[marioc89]

I understand all of what you said. But what I am telling y'all is that, I'm not driving in 4wd mode. It feels like it with the vibration. And I'm asking you, what can I look to to see why it feels that way. And this is while I'm in 2wd mode. And I have read my owners manual and it states that you can put it in auto mode on wet surfaces and drive normally. But my only concern is the unnecessary vibration in 2wd mode. Only that.

[Hawairish]

You mentioned 4wd indicator light being on, and discussed vibration in the context of being in 4wd...

You can be in Auto at any time, or all the time. The vehicle will assess when to engage the front drivetrain (by engaging the transfer case) as conditions permit (i.e., any time there is a traction delta between the front and rear tires). In 2wd mode, the transfer case does not engage...however, on your vehicle, your front drivetrain (CVs, differential, driveshaft) is always rotating regardless of driving mode. (The only exception is if you have manual locking hubs, which I don't think you have.)

If you have a vibration while in 2wd, it could be either the front or rear drivetrain. You can only diagnose it by disconnecting driveshafts. But before I'd ever do that, I'd be checking the tires, springs, and shocks.

Did this vibration just start occurring?

[marioc89]

My tires are new. My suspension has just been done along with rear upper and lower control arms. Front driver lower control arm has just been replaced as well. It started before I did the control arms but some time after the tires. I know the vibration could be attributed to many things. So I'm pretty much left confused on where to start. I just would a little guidance on my first out look. How can I check the transfer case fluid level, now that you mentioned it.

[yeldogt]

Driving on dry pavement with the system in the "Auto" position should be exactly the same as when it is in 2WD. Is the ABS working correctly ? The 4WD system uses the ABS and the traction control to engage the 4WD.

[marioc89]

Yea. Everything works perfectly.

[yeldogt]

I can't explain why you would be getting a vibration in 2WD -- this is something that will have to be checked on a lift.

In wet weather the wheels will slip easier -- so it does not strain the 4WD system as much. Although I don't see the benefit of using the 4WD in the rain unless it is of biblical proportions and the road is completely flooded.

The only time I put the truck in 4WD is when I'm driving on ice or snow -- you should be getting the center light on the pictogram when in 4WD.

The transfer case could be getting stuck? Have you recently changed the fluid? done anything ease to the drive system? How many times has it cycled through?

The transmission and the transfer case both use the Nissan D Matic fluid -- the differentials use gear oil. You may have the limited slip in the rear. I'm not saying that a fluid change will fix this -- just for information. When I bought my recent 02 LE a few years back w/64k ... I changed out all the fluids. Mostly, because I wanted the levels checked -- it's not much more work to drain and refill everything -- I don't remove the pan on the transmission (simple fluid change). The 02 LE I bought new went about 110k before I changed them.

I have owned three 02 LE's with the motorized transfer -- This last one was owned by a women who rarely drove in bad weather -- I'm not sure why she even wanted a 4WD vehicle. It's quite possible that mine never engaged the 4WD until I owned it.

[Hawairish]

Have the tires re-balanced. Not uncommon for wheel weights to come off.
You can also try rotating the tires to see if the vibration ceases or changes.
At what speeds does it vibrate? Do you feel the vibration in the truck, steering wheel, or both?
Have you had an alignment recently?

[marioc89]

I feel it throughout the truck, if you will. The same feeling you get when its engaged on all fours driving at high speeds around 45-50. It's nothing alarming but just concerned. This is a great truck that Nissan built and I just want to take care of it. You know.

[marioc89]

Is there a write up on how to check and change the transfer case fluid and so forth? I had a thread on if I should change my transmission fluid or not, but I'm still undecisive about that because I'm not convinced either way.

[Hawairish]

The same feeling you get when its engaged on all fours driving at high speeds around 45-50.

No one should be driving in 4H at that speed to find out the feeling.

I'd suggest not drawing comparisons to the 4wd system if you're trying to diagnose a vibration problem while in 2wd; 4wd systems don't introduce vibration. All the vibration-susceptible driveline components (driveshaft and u-joints) are constantly in rotation anyway on your vehicle, regardless of driving mode. And by the way, the typical sensation felt when 4wd is engaged is actually a tightness in the steering, and not really anything else.

Changing fluids is trivial, but not the source of vibrations obviously. On the t-case, you have a fill plug and a drain plug. To check the fluid, open the fill plug and look inside. The fluid level should be up to the bottom of the fill plug hole. To replace it, open the fill plug first (always) and then the drain plug. Install the drain plug, pump/pour fluid into the fill plug hole until it starts to pour out same hole, then install the fill plug. The transmission (as well as front and rear diffs) isn't much different, although the transmission also has a dip stick for checking the level. Refer to the FSM for the process, location of the plugs, and fluid capacities.

[marioc89]

Ugh! Omg. I'm not referring to 4h. Why do keep going to 4h. When I speak of 4wd, I'm referring to auto mode when all four lights illuminate. I never mention 4h. I know the difference. Lol.
And thank you for the input on the fluids. And I know too that fluid doesn't have anything to do with vibration. That was aside from what I'm initially asking about.
But I may even check my wheel bearings to see of any issues too.

[yeldogt]

The reason we keep going back and forth with you is you keep talking about 4WD. When the car is in "Auto" it's not in 4WD.

First you need to make sure that the truck is not stuck in 4WD -- this should be easy to figure out. If it is .. that's your problem.

If not .. move on to locate the vibration.

The center differential light will illuminate when you place the truck into 4WD high. Is your light illuminated when in "Auto" -- it does not light up in "AUTO" ... the 4 wheels are illuminated.

The transfer case uses auto trans fluid -- use the correct fluid! Nissan D matic. I bought a case off of e-bay and did both -- simple refresh on transmission -- no removing the pan and transfer case. Believe I used just under 6 quarts.

do a search -- I talk about it someplace

[Hawairish]

Ugh! Omg. I'm not referring to 4h. Why do keep going to 4h. When I speak of 4wd, I'm referring to auto mode when all four lights illuminate. I never mention 4h. I know the difference. Lol.

Actually, I don't think you know the difference. We keep referring to it because you're poorly describing a scenario in which you feel vibration that you correlate to what you perceive occurs when in 4WD. You've drawn that conclusion twice now.

You don't have to mention 4H...you mentioned "AUTO", which means your drivetrain can be "automatically" put into 2H or 4H at any given time or speed, conditions permitting. Or in a malfunctioning or non-maintained system, it remain in 4H. Of course, as mentioned multiple times, your entire driveline spins regardless of what mode you're in.

I doubt you've looked into any of the other suggestions anyway...you know, the things that any one else would do to see if they could isolate the source of vibrations. You could have removed the front driveshaft in 15 mins to see if the vibration ceases, but I guess now you're dragging the wheel bearings into the equation...

If the vibration is not a problem for you, then don't make it one for us. Me personally, I consider any vibration concerning—vibrations lead to fatigued parts, and fatigued parts lead to prematurely-failing parts.

[marioc89]

The reason we keep going back and forth with you is you keep talking about 4WD. When the car is in "Auto" it's not in 4WD.

First you need to make sure that the truck is not stuck in 4WD -- this should be easy to figure out. If it is .. that's your problem.

If not .. move on to locate the vibration.

The center differential light will illuminate when you place the truck into 4WD high. Is your light illuminated when in "Auto" -- it does not light up in "AUTO" ... the 4 wheels are illuminated.

The transfer case uses auto trans fluid -- use the correct fluid! Nissan D matic. I bought a case off of e-bay and did both -- simple refresh on transmission -- no removing the pan and transfer case. Believe I used just under 6 quarts.

do a search -- I talk about it someplace

I may have used 4wd in correlation to all four lights being on. Not meaning true 4wd. Pardon me for not being thorough. But when I put it in auto, yes, all four lights light up and it isn't stuck in 4wd. The truck actually drives great and smooth, which is why I noticed the difference in the driving. Thanks for your input man.

[marioc89]

Ugh! Omg. I'm not referring to 4h. Why do keep going to 4h. When I speak of 4wd, I'm referring to auto mode when all four lights illuminate. I never mention 4h. I know the difference. Lol.

Actually, I don't think you know the difference. We keep referring to it because you're poorly describing a scenario in which you feel vibration that you correlate to what you perceive occurs when in 4WD. You've drawn that conclusion twice now.

You don't have to mention 4H...you mentioned "AUTO", which means your drivetrain can be "automatically" put into 2H or 4H at any given time or speed, conditions permitting. Or in a malfunctioning or non-maintained system, it remain in 4H. Of course, as mentioned multiple times, your entire driveline spins regardless of what mode you're in.

I doubt you've looked into any of the other suggestions anyway...you know, the things that any one else would do to see if they could isolate the source of vibrations. You could have removed the front driveshaft in 15 mins to see if the vibration ceases, but I guess now you're dragging the wheel bearings into the equation...

If the vibration is not a problem for you, then don't make it one for us. Me personally, I consider any vibration concerning—vibrations lead to fatigued parts, and fatigued parts lead to prematurely-failing parts.

Actually I do know the difference sir. You so poorly took it with your own thoughts. If you really want to get technical, I used 4wd and did not mention anything about 4h or 4L. Again, what I was referring to is the four lights on the dash, hence why I used 4wd. And any giving moment, the front axle will engage if the system detects slippage. Yes. I get it.
And you're right, I didn't look into any of the suggestions that you've mentioned only because I'm out of town on business with the very truck we speak of. I have no means of getting underneath to check what you have suggested.
When the time permits, I will do so.
I mentioned the bearings as a side note, not to mistaken them for a drivetrain part or anything pertaining to a transmission of some sort. I'm not novice but I can admit when I'm a bit lost.
I thank each and everyone of you for your time and help.

[marioc89]

So. To give you an update on this matter. The problem came out to be a worn u joint going into the transfer case. It was causing the unusual vibration. Since it had a little play, it caused the drive shaft to go off balance as it was rotating. So. That was it. Just wanted to post this so that others could search and find this to help them.