aj_berg

Hello everyone! I am running out of options as to what the noise is on my front driver tire. It is a constant 'whirring' noise that increases with tire speed. I hardly feel it in the steering wheel, but there is a slight vibration that occurs with it (I can feel it with my feet on the floor) and you can definitely hear it, especially at speed. I started with the bearing and hub assembly, replacing that, along with rotors and pads while I had it all apart. Noise still occurred. I then replaced the front axle U-joint, thinking that would take care of it. Noise is still present and not any better after replacing all parts. Anyone have a next option? Thanks in advance!

Andy

Thernlund

Any unusual tire wear? What kind of tires?

Is it possible you only hear it on the driver's side because that's the side you sit on? Can you let someone else drive and take it for a spin with you in the passenger seat and see what you hear?


-T.

PatHenry

X2

PatHenry

I'd rotate the tire on the side in question with another (like pass side rear) and see if the noise changes. If so, you know it's related to the tire/wheel.

aj_berg

Hey guys,

Yes, as the sound has progressed over the last few weeks, I have asked the few people that have sat shotgun, and they all say it sounds like it is in the driver's front area. Also, there is no uneven wear whatsoever in any of the wheels. I have rotated the wheels to try and verify as well. After rotating, the sound is the same, from the same area (eliminating a balanced wheel issue I would assume?).

-Andy

Thernlund

Well, the front drive shaft is on that side. Maybe take it out and drive around without it, see if that might be it.


-T.

PatHenry

If you're sure the Tires, Hub/bearing, brakes and axle u-joints are all good, then the problem may be coming from the differential or front drive-shaft. (Being that the differential "pumpkin" is offset to the drivers side, this could very well sound like it's a drivers side wheel sound.)
I'd start by checking the fluid level/condition in the front diff and then inspecting and greasing the front shaft. If the culprit does not jump out at you, I'd then remove the front drive-shaft and drive around a bit and see if the noise is affected.

Somebody smarter than I may have additional/better advice, but that's the route that I'd take.

Edit - By "inspecting the front shaft", specifically I mean checking the u-joints are all tight and looking for any damage or obvious trouble. Additionally, if there are signs of severe leaking from the pinion seal on the back of the diff, that would lead me to check the pinion bearing as they are a common failure point.

aj_berg

Thanks for the input! I think my next step will be to remove the shaft and see how it sounds going around the block. I just put in the new u-joints last night so I'm sure they are good. What else could be the issue with the driveshaft otherwise? I will also inspect fluid level and for possible leaks in the differential. Thanks again,

Andy

PatHenry

There are 3 u-joints in the front shaft, any one of those could be bad. (I'm assuming your new u-joints are in the axle shaft that is connected to the wheel hub bearing.) There's a centering ball in the double-cardan part of the front shaft that is also a wear item.
The pinion bearing in the front axle could be bad.
There are bearings in the front diff that could be bad or there could be a problem with the diff gears.

aj_berg

Pat, thank you for clearing that up. Because it sounded like the front left corner, I had only looked as deep as the axle shaft, but being that the differential is offset like you said, I could see it very well being that as well. I'll look into these areas and see what I can find after work. Thank you.

Andy

Thernlund

One thing you could do is put the Jeep on four jack stands placed wide on the axles so that all the wheels are off the ground. Then put it in 4WD, put it in gear, see what you hear. Being able to move around the Jeep while the wheels turn may or may not reveal things. The diff will cause the wheels to spin weird, so don't go fast or anything. But if something is wrong you should be able to hear it and maybe pinpoint it by moving around it.

(As a note on safety, make sure there is nothing in front of the Jeep when you do this. Don't walk in front of it, don't get underneath it, just look from a distance, and make sure there is someone in the driver's seat at all times, if not you then someone. Be careful!)


-T.

aj_berg

So I climbed underneath again after work. First off, the differential lube was not flowing out of the fill hole, but it was at a slight angle being in my garage (gear lube was just under the fill hole). Second, I greased the driveshaft zerk, thinking it would be fairly dry as I usually only hit that every few oil changes or so. It was not, and grease began flowing out after a couple pumps. I played with all three bearings in the front driveshaft and truthfully, none felt bad at all; very solid. I realize this isn't the best test, but again, all felt and looked very solid up close. Finally, the pinion bearing on the rear of the differential does have a leak. Nothing is dripping, but I can see a wetness down the side of the differential. I searched this issue, and it looks like most people that search the issue have a visible or noticeable to the touch looseness on the seal, whereas mine is nothing close to that, just the noticeable wetness.

Side note: I did not take the front axle out yet to see if it made a difference. I wanted to see if anyone had any suggestions first. Will most likely take out tomorrow after work though to test.

Thanks everyone!

-Andy

PatHenry

I think you definitely have to try removing the front shaft. Beyond that, as was suggested, you aught to jack up the front end and spin the tire and see if you can hear the noise.

A mechanics stethoscope might be helpful (or the long screwdriver trick) to pinpoint the location.

Was there any weirdness with the brakes? Like a discernible amount of extra wear on the driver's side?

aj_berg

Hey guys - I finally had a chance over the weekend to get back to the Jeep. I removed the front driveshaft - noise still exists. I have had the front end up a handful of times now, spinning the front wheels, but have not been able to hear anything out of the ordinary. Brakes were wearing evenly between both sides, and pull the same now with new rotors and pads. Given this, it seems to me that it could only be the differential? Any feedback helps - all of this is a first for me. Thanks!

- Andy

PatHenry

I'd jack the front end up and listen closely at the differential and see if you can hear the noise there.
If you can hear the noise there, see if you can isolate it to the pinion bearing (back) or diff gears (front). If it's more to the front then I'd pop the differential cover off and drain the gear oil, then with the wheels off the ground turn them and see if you see or hear anything funky with the differential gears.
There are 2 bearing retainers that hold the gear assembly in place (with accompanying bearings, of course) - you have to pull both the axle shafts out and then you can remove the gear assembly. Be super careful if you do that that you note the exact orientation of the bearing caps. They have to be reinstalled EXACTLY as they came out. I'd use a cardboard box, label top and bottom and zip tie the bearing retainers to it or something like that.
Gear oil is messy and stinks, so I'd make sure the sound is differential related before opening it up.