2001 QX4 vibration,Transfer case?

[Gregk604]

I am no expert but considering you have visible wear I would be replacing the shaft. You should be able to pick one up pretty cheap (I just got a new rear shaft of craigslist for $40) Something to consider - by flipping it you are now reversing the rotation of of the shaft. Not sure what impact this might have on already worn u-joints. The good news is you don't have the vibration anymore and now know what the root cause was.

[t0ast3r]

Hello all...new here (first post)!
Just bough a 2004 Pathy and this thread really helped....glad you all found your issue, now I have a solid point to start from! I will start my search for a new rear drive shaft! CHEERS

[4xq]

RGK, have to give you a couple of points for thinking outside the box! Very few driveshafts can be installed "backwards", so I have not seen anyone try that.

Will it last?. It is kind of a guess - I really don't know. As far as driving it like that, I don't see any reason why you can't. It won't fly off the truck, so might as well try it.

Keep us posted!

[rgk]

Thanks, I wish I could take credit for coming up with that, saw someone suggest it in a thread at some point.

[lipewms]

Can anyone tell me if I would be ok/able to drive my QX4 without my front drivers side drive axle in?
As I have been driving this thing going on a yr now, I'm starting to think my "vibration" is coming from the front bearing or bent axle...just wondering
Thanks in advance
Lipewms

[rgk]

I wouldn't do it permanently, as I dont know what that would do for the transfer case, but you most certainly can as a temporary test of the front shaft.

The rear shaft drives the transfer case fluid pump, so your fluid will still be circulating throughout.

If your vibration goes away after removing the front shaft, order yourself a new one. They're about a hundred bucks at online junkyards.

I flipped mine 180 degrees about half a year ago. Initially the vibration went away completely, then came back but never got as strong. I have been living with it since. It doesn't bother me so much anymore and does not affect my 4WD.

[lipewms]

Thank you rgk, I am under the impression that the bearing (if there is one here) in the wheel "yoke" (connected to the strut,steering end and lower balljoint?) is bad, turns out the vehicle was hit at this wheel location and I think there may have been damage to the bearing or axle shaft...when in 2 wheel the vibration happens lightly and at about 40ish Mph but in 4 wheel the vibration happens at about 57-60 and is a hard vibration and felt in the steering wheel while giving it gas, but it stops when I let up on the gas and coast back down to a powered (give it gas again) drive if that makes sense...I'm thinking about doing this in the spring now that the snow has flown...
thanks again rgk
Lipewms

[rgk]

If it hasn't been done before, then removing the front shaft will be a pain. You will need a box wrench, a flathead, and plenty of elbow grease.

Put the flathead in between the u-joint and wedge it against the body to prevent the shaft from spinning. Put the box wrench on one of the four nuts that hold the u-joint to the end, then put as much torque as you can on it. If I remember correctly, I had to use plenty of penetrating oil, hold the box wrench in place with one hand, then strike it with a hammmer to break the nut free.

All of this while laying on your back while dirt and grease falls in your eyes. Good times.

Wear eye protection, and don't forget to chock the wheels! You will be moving the differential back and forth, and the car may roll on you. After you've loosened two of the nuts, you'll have to move the car a few feet to rotate the shaft and get to the other two nuts. Good luck. Once you've done it a first time, any time afterwards is a breeze. I recommend letting the penetrating oil sit for a while before beginning the work.

[carnal_c30]

I had a similar 45mph+ vibration issue on a 2002 QX4 in 2wd,4wd it didn't matter. It was indeed the front drive shaft.

I've never had an issue with the R50s but failed drive shaft Center Support Bearings can be a cause of vibration on Nissan trucks (replaced twice on my D21 hardbody.) Inspect for any tearing or signs of bearing failure. Ofcourse it can all go together- bad driveshaft/ujoints can cause the bearing to fail prematurely.

[donald]

Success!

I have been chasing this vibration issue since January. Putting another rear drive shaft completely solved the issue. I'm gonna cut the old driveshaft in half and see if there is a harmonic balancer inside.

Yes I cut my shaft in half, there's nothing inside as I expected. Seems the first shop just did a poor job on the balancing.

I was a little nervous driving with the rear shaft out for that exact same reason. There is an electric pump in the transfer case that activates in certain situations, one of them being in neutreal and low speed or in park. You could always drive a mile, idle in park for a minute, repeat. From the FSM:

The transfer motor drives the sub-oil pump to provide proper lubrication and oil pressure control when the
vehicle is at standstill, during low-speed operations or is being driven in reverse.

The main oil pump is operated by the driving force of the mainshaft. In other words, sufficient oil pressure
buildup does not occur when the vehicle is at standstill or during low-speed operations. While the vehicle
is being driven in reverse, the main oil pump rotates in the reverse direction. Therefore the main oil pump
does not discharge oil pressure. During any of the above vehicle operations, the transfer motor drives the
sub-oil pump to compensate for insufficient oil pressure.

Cheers!
and thank you for withstanding all that frustration for the rest of us.
Glad to hear you got your answers!

[rgk]

My vibration returned a few days after I spun my driveshaft around. I drove around with it like that for about six months. I then finally replaced the differential fluids for the first time in the vehicle. After two test drives, I can say that about 90% of the vibration has gone away. I'm glad I never replaced the driveshaft. So if you have a vibration, and your differential oil hasn't been replaced in over two years, do it! The rear diff was a bit low on fluid and had quite a bit of shavings on the magnet. The front fluid looked good when I stuck my finger in the hole, but when drained, it was quite black.

[Densetsu]

I had similar issues that required a three-step approach. Initially there were moderate vibrations felt through the steering wheel around 70-80 km/h, and it got a worse at highway speeds. It wasn't severe vibrations, but it was enough for my Fitbit to think I was rapidly tapping it -- it kept going into "sleep mode".

1. I jacked up the front end and found my driver front wheel had some side-to-side play, even though the lugs were torqued properly. I re-packed the hubs and inspected the bearings (which looked good). The side to side play went away, but the vibration was still there.

2. I found some play in the front driveshaft as well. I replaced both of the front u-joints, and that fixed the vibrations at the 70-80 km/h mark. There was still some minor vibrations starting around 90km/h when in 4WD Auto, but nothing like before. It was summer and I was in 2WD almost 100% of the time, so I ignored it.

3. Winter's came and I usually keep it in 4WD auto from November to April. The vibrations were annoying and getting a bit concerning, so I finally drained and refilled the transfer case. The stuff that came out was near-black and almost had a hint of grey/silver to it. Not good, and nothing like the dark red stuff that came out of my transmission a few days earlier. Took it for a test drive, and the vibrations are gone.

tl;dr: Re-packing hubs and replacing the front driveshaft's u-joints got rid of the major vibrations, but it wasn't until I swapped the transfer case fluid that all the vibrations disappeared.

Fun side note: When I replaced the gear oil in my differentials last year, the oil wasn't black -- it was dark grey. The ATF in the transfer case having a silverish look to it reminded me of that gear oil. I really need to get on top of maintenance besides oil and transmission.