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Hi all, just joined the forum and have gotten good info here in the past My auto mechanics knowledge is limited and I need some help. I have an early '07' that had a bearing go bad in the rear differential. The shop I took it to replaced all the bearings but said the pinion gear was OK. The problem I'm having which may or may not be a problem is that I have a gear winding sound when I have the accelerator down and it stops when releasing the accelerator. I also get a gear winding down sound when coming to a stop. I brought it back to the shop and they just replaced the fluid and said it should solve the problem. I thought this didn't make much since at the time and sure enough I have the same noise. This isn't a very loud noise but loud enough it makes me wonder if something wasn't put back right and is annoying. Can some of you mechanics on here tell me what the problem might be and if it's something I should pursue further with the shop or if it's probably nothing to worry about. Thanks Ron
 

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A new differential should have its fluid changed after the 1st 100 miles, or so, to clean out any metal resulting from its bedding the teeth to each other. That bedding process (new gears) might make some additional noise, for a brief time (and it will run hot, so should not be driven hard until after that break in is completed).

But a diff which only got the bearings replaced should not make any new noise. Typically, a noise on over-run is a sign the teeth are not aligned properly and will result in premature wear unless corrected. Or, it could be sign that when the bearing went bad some permanent damage was done to the teeth.


Norm
 

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I’ll guess that they have preload on pinion bearings incorrect.
The bearings are too tight possibly because a new crush sleeve was not used, or torqued correctly.

This diff will fail in time. I suggest finding a shop that’s knows Toy differentials. It will require a redo.

IF this whine was there before rebearing, it is possible the ring and pinion has a bad match now. Once a R&P gets a bad wear pattern, it usually cannot be corrected.

Again, find a shop that specializes in regearing differentials.

Hard to diagnose over the internet but my experience on LC diffs as well as years building class 8 truck diffs , raises a red flag for me.
This noise will not go away, and it will not fix itself.
JMHO


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After rereading your post , I believe the gear mesh pattern is incorrect, or damage was done to the orig gear set that can’t be corrected without a new gear set.


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Did they tell you what caused the bearings to fail?

Low lube from a leaking seal?
Wore out from use?

You didn’t mention how many miles was on your vehicle.

Like has been said, not every mechanic knows the proper way to set up the ring and pinion clearances so they mesh correctly and wear normal.
This is a time you don’t want a cheap fix.
Most who have diff problems replace bearings, seals, ring, and pinion while there.

It’s easy for us to armchair mechanic on the internet but it sounds like you still have a problem.

You might have to pay twice on this project to get a reliable diff.
 

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Hard to diagnose over the internet...

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It’s easy for us to armchair mechanic on the internet but it sounds like you still have a problem.
This and this.

Did they replace the pinion bearings or only the side bearings? Doesn't really matter because it will need rebuilt again. I recommend OE Koyo bearings and a quality gear set.
 

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When a bearing (or bearings) in a planetary gear set up (rear differential is a good example) go bad, the gears become slightly misaligned and the teeth on the gears wear differently in the skewed alignment. When using the same gears with new bearings, the proper alignment of the worn teeth make noise. Depending on how long the bearings were bad (gears misaligned), the teeth of the gears may still last a long time. If the noise bothers you, replacement of the gears is the only remedy to mitigate the noise. Shouldn't need to replace the bearings a second time, because new gears with good bearings will create a good marriage of the gears and silence the whine. This assumes that the mechanic shop properly spaced the gears with the new bearings during the first repair.
 

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2007 are notorious for having rear differentials issues. The exact issue you are having I had in 2017/18; bottom line had to replace the pumpkin because the gear teeth were wearing down. Since replacing no more issues, no more noise. Good for another 100k plus miles. Hopefully this helps you.
 

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2007 are notorious for having rear differentials issues. The exact issue you are having I had in 2017/18; bottom line had to replace the pumpkin because the gear teeth were wearing down. Since replacing no more issues, no more noise. Good for another 100k plus miles. Hopefully this helps you.
No.

2007 - 2009 model years - rear diff problems were limited to a specific range of VIN#'s.

Failures on early FJ's were due to overworked overloaded FJ's that were at or beyond the 8" capacity.
 

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I think he was referring to the 07's issue with bad ring and pinion from the factory. Almost all broke teeth due to a bad batch of gears and were replaced under warranty.
 

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I think he was referring to the 07's issue with bad ring and pinion from the factory. Almost all broke teeth due to a bad batch of gears and were replaced under warranty.
Yes.

I should have been clearer.

The bad batch of gears were limited to a specific VIN range not all '07's.

Other '07-'09 were due to the 8" being overloaded/worked. Back the people figured the FJ was indestructible and would wheel with everything including the kitchen as well as other limit testing stunts.
 

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So where is Toyota's publication with this VIN range information? I'll start looking through my customer's numbers.
 

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I do recall it being post here, I'll have sometime later to look for it.

It was posted around the same time as the VIN range for the bulging tires.
 

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I never got a recall noticed and I didn’t overload my FJ and did not have a 8 inch lift. Just 3 inch lift, Gear teeth failed @ 118k. Still love my FJ but ****ty gears from Toyota.
 

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I never got a recall noticed and I didn’t overload my FJ and did not have a 8 inch lift. Just 3 inch lift, Gear teeth failed @ 118k. Still love my FJ but ****ty gears from Toyota.
NO .

That is not what Mikey says . >:D

I think you filled your FJ with concrete and did full throttle neutral drops in front of the high school . :blueblob:

untill you can prove different . that is what you did :rofl:
 

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Just out of curiosity - which bearing failed? What exactly was the problem with it?
 

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Ron, you need to swap out your diff. The bearings in your diff will make a rumbling sound at slow speeds and winding a freeway speeds when there’s an issue. Not the bearings. Your gears will make a whining sound. If the shop reused the gears they’ll have a pattern worn into them which can’t be matched perfect again. That’s where you’re noise is coming from. Your diff won’t fail but will get whinier with time as a new pattern is worn in. Just order a complete 3rd member from ecgs for about $750 after return of the core and call it a loss. Don’t ask me how I know all this . I’m a 2007 owner who’s kicking myself for doing a rebuild and reusing the gears, and not ordering a complete 3rd member from ecgs the first time.


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