Clicking from left rear, sounds like bearings to me, what do you think?

[jasandunlop]

Noticed a strange clicking sound in the left rear of my 2010 SE 4X4 after trying to pinpoint the cause of some pretty significant cabin noise between 10-20MPH (truck has 96K miles and is out of warranty). As speed increases, I don't necessarily think the sound goes away but is muffled by wind, traffic, and tires. Put the rear on jack stands, pulled tires and put the truck in gear to take a video with sound, clicking still present. Pulled calipers and rotors, clicking still present. After researching parts and the apparent propensity for Xterra differential problems, I decided to drain the differential (just changed <10,000 miles ago) and found a bunch of metal on the drain. When I changed the diff fluid previously, the magnet was very clean. I'm a DIY'r but have zero experience with the rear differential, other than changing the fluid. I pulled the cover off the rear diff, hoping that if anything was wrong, it would be blatantly obvious. Put the truck in neutral and turned the wheel to get a good look at everything but didn't see anything obvious. Right now I'm thinking about ordering the left rear axle shaft assy; it includes the bearings and is pretty much plug and play (after getting the old one out). The shaft assy is ~$320, which isn't peanuts but is cheaper than the entire axle @ ~$2K. Going to try and attach a couple of videos, one of which was taken last night after I put the rotor and caliper back on. Video identifies the sound at the left rear wheel well, shows reduction in sound as the camera moves from the outside of the wheel well towards the differential, and also shows the sound inside the cabin. Second video is of the differential with the cover off, I didn't see anything wrong but maybe someone with more experience can highlight something (I hope not). Also attached a pic of the drain and magnet with metal shavings (why? I don't know). Videos were much to large @ 127meg, so here are the locations on YouTube
Rear-end noise https://www.youtube.com/watch?v=iT3LMgSaryQ
Differential https://www.youtube.com/watch?v=Erjmybzmpec

 

[granitex]

typically bearings don't click, they start to groan and droneand will change pitch with speed.

 

[jasandunlop]

Thanks for the quick reply. I was thinking that as well but all the diagnosis points to something around the bearings. I'm going to try to pull the axle shaft tomorrow and I'll post my findings. Quick question. In many of the axle shaft removals I have seen, there is what looks like a sprocket on the outboard side of the bearings. What is the point of this sprocket? I guess my clicking could be something associated with it. Guess I'll find out tomorrow.

 

[metzican]

Is it possible that you bent an axle shaft? I had a similar sound when I did that. But my noise was from the diff.

 

[jasandunlop]

Pretty impressive list of mods Metzican, and great looking truck. I guess anything is possible but not sure how I would have bent it. I didn't add a ton of details regarding the use of my X because the post was already so large. My X has never been offroad (unfortunately) but is used to tow. I've towed toys, ATV and kids dune buggy, 20' boat, and a 12' trailer for home projects etc but never tow long distances.

Hopefully I can borrow a puller today and locate/purchase the bearing and seal locally. While I have the shaft out, I'll definitely inspect for straightness and if anything is found, take pictures.

Thanks,

 

[metzican]

It takes quite a bit to bend our axles. I did mine when mine got rear ended directly on the tire by a car. Others have done it while off-roading if I recall but not just the standard easy stuff. I thought maybe you hit one of those Florida sink holes or they migrated up your way.

 

[jasandunlop]

Pulled the left rear axle shaft to check the bearings. With the shaft removed, the bearings didn't make any noise at all. Prior to removing the shaft, I checked for any wobble, or inconsistent spacing while turning the hub, which would indicate the shaft was bent. If the shaft is bent, it's internal to the axle and even though I tried checking, my methods for checking weren't nearly precise enough to identify a slight wobble. I was hoping it would be bearings, so I didn't have to deal with the differential but it seems the sound originates in the differential and resonates down the axle shaft, making it appear as though the ticking is being caused by something around the hub. Put everything back together until I can get the car into my old mans' shop in SC. He has all the equipment (lift and tools) and knowledge (50 years experience as a mechanic) to dig into the differential, and his labor is free. Sounds like a great fathers day project. If this thread is still active following the differential work, I'll update it with the results.

 

[emtmark]

Looking forward to it, solving of the mystery that is.

 

[Intender]

Well, hopefully you can get this figures out. And the sprocket you were asking about is the ring for the abs. It uses it to determine your speed.

 

[wbrennan]

I started getting a thumping noise out of the rear right rotor not three months after replacing rotors, disks, and bearings. Had the rear rotors replaced with new under warranty not quite a month ago and right after a car wash, the sound is back. Extremely frustrating but I think I may take it back to the service shop and see what they find....when I'm due for diff oil will definitely want to peek at the plug to check for metal.

 

[jasandunlop]

Thanks Intender, I figured that out when I pulled the ABS sensor. The one thing I did notice when I pulled the shaft is that the oring between the ABS sensor and the hub wasn't doing its job completely. There was some rust in the cutout for the sensor and some scoring which appears to have been caused by the rust pieces breaking off and getting ground down as the ABS sensor was rotating. I have quite a few pictures which were taken during this procedure, which was really quite simple. If the axle shaft removal has not been covered previously, I would be happy to post a How-To. After speaking with the old man, he had a couple of questions which I tried to find answers to. The first, is this a limited slip? According to him, the clutches could be a problem but I don't think this is limited slip, it's something else. Here is an exploded view of the
differential. Looks like plenty of gears in there that could be responsible for a ticking sound. I have to travel to Germany next week for a couple weeks, when I return, I'll be spending some time with the old man pulling apart the differential and looking for the ticking timebomb. I'll be sure to document everything. Hope all your wives and mothers have a great mothers day.

 

[jasandunlop]

For those of you, like me (prior to last week), who have never taken your diff cover off to look at the differential, here is what you would see.
[h=3]Here is how a differential looks like inside[/h]

Before you ask, yes, I do have that differential in my living room.

1 flange (attaches to drive shaft) 2 pinion gear 3 side gears

[FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]4 ring gear[/FONT] [FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]5 left axle shaft[/FONT] [FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]6 right axle shaft[/FONT] [FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]7 pinion (spider) gears[/FONT]

Here is what a differential is supposed to do: Always distribute equal amounts of torque to both wheels - react to resistance (traction) to allow the wheel with more resistance (traction) to rotate less and the wheel with less resistance rotate faster (needed in turns where the inside wheel has to rotate less than the outside wheel). The rpm difference between left and right created by the differential is always proportional. If the inside tire rotates 15 rpm less in a turn than going straight - then the outside tire will rotate 15 rpm more than going straight.

 

[Intender]

2nd gens do not have true limited slips. They were either equipped with a e locker or open. If slipping was detected the computer would apply the brake to the side that was spinning faster forcing some of the power to go to the side spinning slower.