Intermittent Problem

T

Tek23

New member
I started having an intermittent “rattling/grinding” noise that started last night. Happens above 10-15mph and only when I lightly press the accelerator. Once i let go, it stops. Doesn’t happen when car is in moving in neutral or dead stopped. Drove to my buddy’s shop earlier today so we could figure it out—on the way it did it for a few minutes. I switched into 4wd, noise went away. Switch back into 2wd, noise never came back till later tonight. Can’t determine if it’s coming from the front or back.

Not sure if it’s relevant but lift kit was installed last weekend.

YouTube link
https://youtu.be/Kt84Uv-tfFs
 
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Does the noise change if you're turning? maybe try to get the noise going and jerk the wheel left and right. Could be the brake dust shields dragging or something dumb like that.
 
LookAtThatDog said:
Does the noise change if you're turning? maybe try to get the noise going and jerk the wheel left and right. Could be the brake dust shields dragging or something dumb like that.
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I haven’t tried jerking the wheel either way. Will do tomorrow. Hoping its something stupid
 
Sounds like something is very loose. Have you gone under there any tapped away with a mallet? Maybe a heat shield or the skid plate?
 
Dam gremlins! :gun4: .... Sounds like a axle sense it went away in 4wd, I'll need to think on it some more been drinking beer tonight so my listening skills are rather questionable .
 
Could be the substrate coming loose inside the cat(s) although they usually rattle more when sitting at a stop sign. Just something to look out for.
 
My mechanic told me to turn up the radio.... LOL
no seriously though make sure everything is mounted right, check skid bolts. see if oil change change didn't forget any since that is cheap quick fix...
but if happens when applying acceleration, sounds like a bigger problem.
 
I missed reading you recently put a lift on. The increased angle of the driveshaft could have put extra strain on an already failing u-joint and now it's really needing to be replaced. I would jack up the rear end of the vehicle and put it in neutral like the video says and check both the u-joints for play.
 
mtbtim said:
I missed reading you recently put a lift on. The increased angle of the driveshaft could have put extra strain on an already failing u-joint and now it's really needing to be replaced. I would jack up the rear end of the vehicle and put it in neutral like the video says and check both the u-joints for play.
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You might be right. Stumbled across this video today and the sound is very similar to this.

https://www.youtube.com/watch?v=yvCejNP_dgo
 
Did you check the u-joints yet? Wondering if that was the cause of the noise you were experiencing.
 
mtbtim said:
Did you check the u-joints yet? Wondering if that was the cause of the noise you were experiencing.
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Checked all u joints and shafts. No movement out of the ordinary. No loose parts either. Drove to work last night and went for a quick ride this morning. It's become an ongoing issue now.
 
Tek23 said:
Video of underneath the truck. Car was on the ground and in neutral.

https://youtu.be/e0j1ek9Mntc
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I don't know if it makes a difference, but the video I sent you a link to had the rear wheels off the ground so he could rotate the driveshaft pushing and pulling up and down on the driveshaft near the u-joints in different positions to check for play. Maybe it only takes a little bit of play to create a noise like that.
 
mtbtim said:
I don't know if it makes a difference, but the video I sent you a link to had the rear wheels off the ground so he could rotate the driveshaft pushing and pulling up and down on the driveshaft near the u-joints in different positions to check for play. Maybe it only takes a little bit of play to create a noise like that.
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I've read/heard both sides of the story regarding the wheels being on the ground. I'm hoping to swing by my buddy's shop and throw it on a lift. Maybe we might be able to diagnose further while he's underneath and I'm driving.
 
Tek23 said:
I've read/heard both sides of the story regarding the wheels being on the ground. I'm hoping to swing by my buddy's shop and throw it on a lift. Maybe we might be able to diagnose further while he's underneath and I'm driving.
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One thing I didn't think of before, but I wonder if you put some grease into each of the rear u-joints, one at a time and then drive it to see if the noise reduces a bit. Greasing them one at a time and then driving would isolate which u-joint it may be. My thought is if the u-joint is bad but doesn't have a lot of play yet, maybe a shot of grease will quiet it down a little letting you know it is an issue. It would be pretty quick for you to do.

Running it on the lift while someone listens from below sounds like a good idea. If there was a way you could mount a GoPro under the truck while driving and putting it in different positions, one near the u-joint near the transmission and one near the u-joint at the rear differential, you could get some footage and hear the amount of noise coming from those different camera locations. If you have a GoPro, they do make different adhesive mounts that might work.

I had a u-joint go bad on a 68 Ford Bronco way back in the day. It was making a lot of racket and I had no clue what it was. At the time, I was working at a Chevron gas station and one of the senior mechanics listened to my truck while driving and immediately knew it was a bad u-joint.

Hope you get it figured out.
 
Of course it doesn't make any noise on my way to the shop or while on the lift. He didn't see anything out of the ordinary. Thoughts on a possible transfer case problem?


Update:: no noise on the way home either
 
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had it on a lift this morning. greased up all the fittings on the driveshaft/u joints.
hoping the noise disappeared since it hasn’t come back since last week but my luck, it came back on the way home from the shop.
 
Tek23 said:
had it on a lift this morning. greased up all the fittings on the driveshaft/u joints.
hoping the noise disappeared since it hasn’t come back since last week but my luck, it came back on the way home from the shop.
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Your quest to figure out your issue sounds like mine trying to figure out the cause of the weird bump at a stop or just rolling from a stop that myself and many other 3rd Gen owners are experiencing. It sometimes feels like somebody bumped your bumper from behind.

I wonder if your issue could be a wheel bearing. Do you notice the noise more on turns where the pressure on the bearing is enhanced and causes the noise?

I think somebody already mentioned CV axles as a possibility, and I know for a fact those can make a decent amount of racket when they're going bad.

Maybe you're mechanic friend could drive it with you so he can hear what it sounds like driving down the road.
 
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