Rear noise when I stop

Tiny
CANNON1349
  • MECHANIC
  • 2011 FORD F-150
  • 3.7L
  • V6
  • 2WD
  • AUTOMATIC
  • 320,000 MILES
Hi,

I can hear this noise when I stop, I think. What do you think? Is it normal? I have the rear jacked up in the air.
Sunday, March 22nd, 2020 AT 12:12 PM

68 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
There is a bit of excessive play between the ring and pinion. To fix something like this requires disassembly of the differential and readjustment.

Are you having any issues while driving? Any noise or vibration when you drive it?

Joe
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Sunday, March 22nd, 2020 AT 1:01 PM
Tiny
CANNON1349
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Not really. Sometimes a clunk vibration when the truck stops at a red light, but I don't know if that's even what this is.

Here's a photo of the differential, I'm changing the fluid now. You think it will help?
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Sunday, March 22nd, 2020 AT 1:09 PM
Tiny
STEVE W.
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Changing it won't hurt but it isn't going to fix worn gears or bearings. If the mileage you have is correct I would say it's just wear, It might be possible to tear down the entire differential, replace the bearings and reset the pinion depth and ring gear lash to make it better but I'm not sure it would make a lot of difference with the wear you have. If you grab the driveshaft at the yoke where you were turning it in the first video can you move it up and down or side to side? That would indicate very worn pinion bearings which could be changed out. Then it becomes a question of cost and return on investment, is the truck in great shape? Is the engine and transmission really good? Do you intend to keep it? If those are all yes, I'd probably go to a salvage yard and find a rear out of a lower mileage truck with the same gearing and options and remove it. Hopefully one that was wrecked in the front as that gives an indication that it was on the road and being used, then use that to build a new axle for your truck. That way you can take your time and still have your truck on the road. Then just swap it out on a weekend when it's ready.
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Sunday, March 22nd, 2020 AT 4:29 PM
Tiny
CANNON1349
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The truck is in great shape, engine and transmission too. I grabbed the pinion and could not move it when I had the cover off. So I guess that's something. Should I worry about it? Or avoid pulling or hauling anything? Or what?
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Sunday, March 22nd, 2020 AT 4:42 PM
Tiny
STEVE W.
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If it's all tight and you are not hearing whining or roaring from the gears I wouldn't be super concerned, I wouldn't start towing a 40 foot camper with it, but normal use isn't going to really hurt it. That is why I suggest the spare unit to work on, you can build it and not need to take the truck out of service until you are ready to do the swap. I've seen them a lot worse and making noises that would raise the dead. On those you plan on gutting the unit and replacing everything, but you have some time before that happens. I would bet there is wear in the transmission as well with those miles, but the same holds for that, it's just a sign of a used vehicle.
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Sunday, March 22nd, 2020 AT 4:57 PM
Tiny
CANNON1349
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But we're talking potentially year (s) right? I haven't had issues and I'm just hoping changing the fluid will slow that down. I only expect to haul my toolbox and drive it wherever.
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Sunday, March 22nd, 2020 AT 7:39 PM
Tiny
JACOBANDNICKOLAS
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Hi,
I agree with Steve. If it starts making more noise or new issues, then a rebuild should be considered. I looked at your pic above. I don't know if it is a reflection or what, but the ring gear appears to have different colors on the teeth. Is that just a reflection?

Also, when stopped, the differential isn't going to cause any shaking or vibrations. That sounds more like a rough idle issue.

Let us know.

Joe
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Sunday, March 22nd, 2020 AT 8:05 PM
Tiny
CANNON1349
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Yes that is a reflection. Also guys, I hate to sound redundant, but just to be sure that video I posted it me moving the driveshaft at the transmission, not the differential. The noise is centered at the transmission end.
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Sunday, March 22nd, 2020 AT 8:09 PM
Tiny
JACOBANDNICKOLAS
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When you said it you had the rear lifted, I assumed you meant it was the differential. That is most likely the parking sprag you hear. Unless you had it in neutral. I attached a picture of what a parking sprag gear looks like. That is what holds the vehicle from moving.

If there was a bearing issue in the tail housing, chances are you would see ATF leaking from it.

Let us know. And no, you aren't being redundant. Feel free to ask anything you want. (Dealing with cars LOL)
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Sunday, March 22nd, 2020 AT 8:17 PM
Tiny
CANNON1349
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Yes, it was parked. Okay so, even if I'm moving the driveshaft at the transmission end, there's a differential issue?
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Sunday, March 22nd, 2020 AT 8:19 PM
Tiny
JACOBANDNICKOLAS
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Chances are everything is okay with both the transmission and differential. There will always be a little play. That's normal. The idea that you serviced the rear differential is a good thing. Most people neglect doing it and it is something that needs done.

Now, if you would have told me that much play was in the differential before the internal gearing connected, I would have told you what I originally said. It's a bit excessive. However, at the transmission, that doesn't concern me.

Can you explain the vibration you experience?

Joe
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Sunday, March 22nd, 2020 AT 8:23 PM
Tiny
CANNON1349
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The gears didn't move when I tried to move them by hand once the cover was off.

Okay. The vibration is extremely hard to explain, but it feels like a "boom."

So when stopping a vehicle, it points downward and returns to normal as you let off the brake. As I stop at a red light I'm braking, and as I inch toward the driver in front and finally stop, there is that boom/vibration as I come to a complete stop. I can avoid this by coming to a creeping stop. Sometimes the same vibration comes from starting abruptly from a stop. This is the first time I've driven my own truck. I know a couple of friends who have trucks and say it's a truck thing. I don't know. Some people have said motor mounts.
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Sunday, March 22nd, 2020 AT 8:29 PM
Tiny
JACOBANDNICKOLAS
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A motor mount may be felt when you first try to accelerate and let off the throttle. Not what you described. Not being there makes it difficult for me, but based on what you described, it almost sounds like a brake hanging up. Think about it. When you slowly stop, you are light on the brake pedal. If you stop quicker, there is more pressure on the braking system. Just for the heck of it, check the brakes. Does it have rear disc brakes or drum brakes?

Let me know.
Joe
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Sunday, March 22nd, 2020 AT 8:46 PM
Tiny
CANNON1349
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Rear disc. I actually just did the front brakes and rotors today and got rid of a brake vibration.
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Sunday, March 22nd, 2020 AT 8:48 PM
Tiny
JACOBANDNICKOLAS
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The rotors were warped. Did you check the rear brakes? I only ask because I did a 2013 Durango last week that had a clunk when stopping and found the parking brake lever (under the rotor) was rusted in place and wasn't properly releasing the brakes. For some reason, when the vehicle was stopped, they made noise when released and starting to move again. It's just a thought. I was able to run the part over a wire wheel, sprayed it down with penetrating oil and got it working again. When reinstalled, the problem was gone. It's just a thought.

It could even be a suspension issue since it happens when stopping fast. Make sure to check ball joints and bushings related to steering and suspension.

Let me know if you have questions or find anything out of the ordinary.

Joe
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Sunday, March 22nd, 2020 AT 9:00 PM
Tiny
CANNON1349
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I checked the rear brakes today, and it's the same story as the front; rotors are under spec while the pads are relatively new. So I'll replace those, but the noise is definitely in the front. I'm sorry, I haven't driven this truck even a week, and I'm trying to make it good as gold.

Again, when I make a complete stop, as the truck halts its movement there is a "boom" feeling and a "boing" like vibration, I've felt this on other trucks before, but I just can't think of anything. A friend said check the ball joints. Maybe the struts are sticking?
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Monday, March 23rd, 2020 AT 7:37 PM
Tiny
JACOBANDNICKOLAS
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When you take the rear rotors off, check the brake shoes for the parking brake as well. If the noise is in the front, make sure the coil springs are in good condition and not broken. Try to record it when it happens. When you said bong, I picture a coil spring. Also, make sure the control arm bushings are good and nothing is loose on the front.

I attached a pic and circled a few things to check. Let me know what you find.

Joe
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Monday, March 23rd, 2020 AT 8:30 PM
Tiny
CANNON1349
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Well, I jacked it up on the control arms and I can't find any kind of movement. I can't see anything obvious.
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Tuesday, March 24th, 2020 AT 2:46 PM
Tiny
CANNON1349
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I have a video here. You can hear the boom as the truck ceases movement. I'm kinda leaning towards sticking shocks despite how expensive they are.
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Tuesday, March 24th, 2020 AT 3:10 PM
Tiny
JACOBANDNICKOLAS
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Hi,

I barely hear it. If it was a shock, you should be able to recreate it by bouncing the vehicle by hand. I wish I could hear it better, but realize that is easier said than done. Do me a favor, check to confirm there isn't any play in the control arms or sway bars. Also, recheck (and you may have already) the caliper mount, caliper slides and so on. Once last thing, make sure there is no play in the wheel bearings.

I literally held the speaker against my ear. I heard something but really can't identify it simply because of volume. I hope you understand.

Joe
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Tuesday, March 24th, 2020 AT 4:45 PM

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