Intermittent Grinding on Pavement.

[jhuerta22]

So this fall, I noticed a grinding sound coming from the front end of my 4runner when I'm at highway speeds. It sounds like metal on metal so I am pretty concerned about what it could be. The problem is, it's intermittent and comes and goes as I drive it. I've tried replicating it with turns, upshifting, downshifting, braking, and about anything else I could think of.

Earlier this month I jacked up the front end, checked the ball joints, CV axles, tie rod ends, U-joints, and brake rotors. Everything felt tight with little to no play. I rotated the tires and that seemed to help for a while, but now I noticed it's back off and on, but not as frequently as it was.

Any ideas on what it could be? Loose brake pad leaning against the rotor maybe? I swapped the factory rotors for the Tundras a couple of years ago.

 

[WeakSauz]

when I'm at highway speeds. It sounds like metal on metal

Just thinking logically, and this probably isnt it: But are your skid plates fastened nice and tight? They could rattle at highway speeds, perhaps mimicking a metal:metal grind?

Otherwise, when you jack the front end up and spin the tires, do you hear anything? Just trying to rule out the front wheel bearings.

Lastly, it could be the needle bearings in the driver side front axle housing. Climb under the truck and try to wiggle the driver's CV with force. If it has gross movement, this could be it. But, usually this is a roaring noise, not so much a grind, so not sure!

 

[gamefreakgc]

Since you did the TBU, is the dust shield bent or scraping on something it shouldn't be?

 

[jhuerta22]

1. But are your skid plates fastened nice and tight?

2. Otherwise, when you jack the front end up and spin the tires, do you hear anything?

3. Lastly, it could be the needle bearings in the driver side front axle housing. Climb under the truck and try to wiggle the driver's CV with force.

1. Yes, they are nice and snug. I don't get much rattle from them.

2. I didn't hear any grinding/metal-on-metal when I spun the tires.

3. "roaring" may be a better way to describe the sound. Kinda like when you hit a milled surface. Hoping and praying it wouldn't be the bearings in the spindles. Is that what you are referring to or in the front diff housing? There is some play in the CV's when I pull on them, but not any more than I noticed when I installed them new 4 years ago. They don't click when I'm at full turn, so I think those are okay.

EDIT: If it were the bearings, would the sound be more constant? It happens infrequently and more so when I've been driving 10-15 minutes. Possibly the heat from spinning causing the bearings to catch?

 

[jhuerta22]

Since you did the TBU, is the dust shield bent or scraping on something it shouldn't be?

I checked those and there is clearance between the shields and rotors. If I recall, isn't there a retaining spring on the calipers that holds the pins/pads in place?

 

[WeakSauz]

3. "roaring" may be a better way to describe the sound. Kinda like when you hit a milled surface. Hoping and praying it wouldn't be the bearings in the spindles. Is that what you are referring to or in the front diff housing? There is some play in the CV's when I pull on them, but not any more than I noticed when I installed them new 4 years ago. They don't click when I'm at full turn, so I think those are okay.

EDIT: If it were the bearings, would the sound be more constant? It happens infrequently and more so when I've been driving 10-15 minutes. Possibly the heat from spinning causing the bearings to catch?

Referring to the needle bearings in the front axle housing:

ECGS Clamshell CV Axle Bushing Install - YouTube

Start at the 8minute mark

 

[gamefreakgc]

I checked those and there is clearance between the shields and rotors. If I recall, isn't there a retaining spring on the calipers that holds the pins/pads in place?

There's an "M" shaped clip that keeps tension on the brake pads so they don't move around. I ended up using two per side as one didn't keep the pads in place.

 

[jhuerta22]

Thanks, Sauz. Yeah, on both sides the wiggle of the CV is pretty bad. I was just tugging on them in and out to see if one wasn't seated in completely. Spot on with your assessment!

Watching the video makes the replacement look like a job for a more experienced individual than myself. Do you have any experience replacing these? It might cost more in parts and tools than hiring it out.

 

[WeakSauz]

Thanks, Sauz. Yeah, on both sides the wiggle of the CV is pretty bad. I was just tugging on them in and out to see if one wasn't seated in completely. Spot on with your assessment!

Watching the video makes the replacement look like a job for a more experienced individual than myself. Do you have any experience replacing these? It might cost more in parts and tools than hiring it out.

If the vehicle you're wiggling the CVs on is the 331k mile one in your sig, this is likely something to address. However, it is a pretty involved job and you'd do yourself a service to verify that this is the actual problem with someone local who knows Toyotas. I would hate for you to tear into it and this isnt even the issue. My gut tells me it is

I've never done it myself, but had a diff built with the needle bearing eliminator already installed

 

[jhuerta22]

UPDATE: I went ahead and replaced the front DS diff bearing with the ECGS bushing. Pretty easy to be honest. I still had the grinding sound, but it was greatly diminished unless I was driving over 50 miles/trip and only when I would be turning slightly left on a decline. I went ahead and bit the bullet and pulled the spindles and had the bearings replaced. She rolls super smooth now! However, the sound is still present. I'm beginning to wonder if it's the passenger side ball bearing in the axle tube that's causing the noise.

From what I've read, there is a needle bearing on the passenger side of the clamshell behind the stub axle tube. This is coming from a 1st gen Tacoma post (not sure if they're all the same components and they have the 7.5" clamshell) but they said they replaced both bearings with the ECGS bearings. Anybody know if there is any thruth to this?

 

[jhuerta22]

Replace front diff bearing- not the needle bearing, the passenger side? | Tacoma World

This is the link that leads me to believe there is a needle bearing on the passenger side that matches the one on the driver's side. About halfway down, Taco '09 stated this:

"The passenger side actually has the same needle bearing up against the diff as the left and it is even the same part number. The difference is the driver's side has a CV shaft directly entering the bearing, but the passenger has a short stub shaft directly entering it as part of the ADD. I have replaced the passenger side needle bearing with the ECGS bushing on two Tacos."

So can anyone verify that the clamshell has the two needle bearings?

 

[jhuerta22]

UPDATE: I was taking a trip a month back that was about 200 miles round-trip and the sound came back. Since then it's pretty consistent from 30 mph on up. Would it be worth tearing off the Passenger side CV, stub axle, and doing the same bearing replacement on the passenger side? I'd love some input. Also, at 343k now so there's a lot going on with the drivetrain and suspension parts that I will need to address in the near future (outer tie rods, rear axle seals, rear brakes, and an alignment). Good news is I managed to snag a spare 3.4 this summer with 115k on the odometer so I'm prepped for when the old dog gives out on me. Fingers crossed it isn't any time soon.

 

[gamefreakgc]

I wish I could be of more help. Front axle repairs is literally the only area of these 4Runners I haven't touched, I've repairs or torn down to the frame every other spot on a 4Runner. Mine also makes a "roaring" noise that I've pinned to either these same bearings or the front wheel bearings. I just keep driving it but it sounds like you're at the point where the 4Runner is really starting to get your attention.

 

[jhuerta22]

Update 06/2022

I wish I could be of more help. Front axle repairs is literally the only area of these 4Runners I haven't touched, I've repairs or torn down to the frame every other spot on a 4Runner. Mine also makes a "roaring" noise that I've pinned to either these same bearings or the front wheel bearings. I just keep driving it but it sounds like you're at the point where the 4Runner is really starting to get your attention.

So, believe it or not, it turned out to be the REAR bearing on the passenger side. I knew the seals were starting to leak, but with the noise coming from the front I didn't even consider it. My friend who did the repair said that it fell apart after the axle shaft came out of the housing. He thought that the noise more than likely was traveling up the drive shaft making it seem like it was a front end issue. I drove it 6 hours back from KC and it NEVER made that sound again.

 

[gamefreakgc]

So, believe it or not, it turned out to be the REAR bearing on the passenger side. I knew the seals were starting to leak, but with the noise coming from the front I didn't even consider it. My friend who did the repair said that it fell apart after the axle shaft came out of the housing. He thought that the noise more than likely was traveling up the drive shaft making it seem like it was a front end issue. I drove it 6 hours back from KC and it NEVER made that sound again.

That's good that you caught it!! Sounds like it was about to leave you stranded.

Unfortunately for me I've already had all bearings replaced in the rear end and still have noise. So I made my exhaust louder so I don't hear it.

 

[jhuerta22]

That's good that you caught it!! Sounds like it was about to leave you stranded.

Unfortunately for me I've already had all bearings replaced in the rear end and still have noise. So I made my exhaust louder so I don't hear it.

Does it get worse or change tone when you switch lanes or turn corners? Is it relative to your speed or RPM?

 

[gamefreakgc]

Does it get worse or change tone when you switch lanes or turn corners? Is it relative to your speed or RPM?

Turning or RPM makes no difference. It's all speed based from 35-65 MPH where some speeds are louder. I've narrowed it down to either the front diff and bearings, CV axles or front wheel bearings. Or maybe front driveshaft.