On My 3rd Front Diff

[rightyouareken]

Can't say that I had the issue off the lot new (summer 2017), but it certainly came into play over the first winter as temps dipped below zero I could hear the groaning, I chalked it up to the bridgestone duellers - perhaps a bad belt. 2018 winter, same noises but seemed to come and go. 2019 winter I became aware of the TSB and since I bought snow tires it certainly wasn't the factory tires now - with the info I was reading I decided to try the dealer (twice) and of course, they never heard anything LoL., so that didn't leave me with any confidence I wanted them tearing into my front end either. Fortunately I have a local off road shop who worked up my Jeep TJ for many years, also very familiar with Toyota trucks in the same sense and were obviously very familiar with this annoyance. They don't use the ECS bearing they use one from Nitro Gear, exact same thing. Anyway - I waited for my warranty to expire and had that tapped in there with the fluid changed out, left the factory seal in (oil was nice and clear - no issues presented even though I thought the groaning was getting louder this past fall), has been smooth and quiet since... so I would recommend to anyone to have that bearing replaced it seems to be a simple process for any mechanic, took my guy an hour... the entire differential assembly isn't the problem I don't know why Toyota is doing that repair - perhaps to avoid recognizing the actual design fault?

Interesting. So you're saying you had a slight noise for the duration of your warranty that didn't really get significantly worse, and that then you had the bearing replaced it wasn't totally destroyed? I wonder if in some cases like yours, the bearing isn't totally failed, just noisy.

I also still don't totally understand why this noise goes away when in 4hi. The left CV shaft rotates the same speed whether the vehicle is in 2hi or 4hi, it's just that the front driveshaft is engaged when in 4hi. But as I understand it, the bearing that is the culprit is the left side output shaft/CV bearing.

 

[17KT4R]

Interesting. So you're saying you had a slight noise for the duration of your warranty that didn't really get significantly worse, and that then you had the bearing replaced it wasn't totally destroyed? I wonder if in some cases like yours, the bearing isn't totally failed, just noisy.

I also still don't totally understand why this noise goes away when in 4hi. The left CV shaft rotates the same speed whether the vehicle is in 2hi or 4hi, it's just that the front driveshaft is engaged when in 4hi. But as I understand it, the bearing that is the culprit is the left side output shaft/CV bearing.

Correct. My guy told me half of the solid bushings he taps in are just for customers like me who have noticed the annoyance, and then there are the others who have their CV angles abrupt that bring the issues on so it puts excessive pressure on those rollers, he has never seen one fail, just wear marks on the rollers but mine was clean... so what can I say - its a design issue I guess, some make noise for no reason other than when it gets cold and there is shrinkage with that metal component - the shaft has extra play and it starts.

The noise goes away with the diff engaged because the other side starts turning, and takes the load off the drivers side CV on the roller bearing... mine did the same - engage the diff, noise stopped immediately (different bearing design on the passenger side shaft)

Anyway - the solid bushing worked for me thats for sure. Its been pretty cold in these parts this winter so it would have been moaning away for damn sure. Some people have said the bushing cured their steering wheel vibe at that magic highway entry speed but I can't say I've ever had that issue regularly. Thats another thing that comes and goes ever so slightly and only with the stock tires and ambient temps. Never on my soft Michelin snows, so who knows...

 

[rightyouareken]

Correct. My guy told me half of the bearings he taps in are just for customers like me who have noticed the annoyance, and then there are the others who have their CV angles abrupt that bring the issues on so it puts excessive pressure on those rollers, he has never seen one fail, just wear marks on the rollers but mine was clean... so what can I say - its a design issue I guess, some make noise for no reason other than when it gets cold and there is shrinkage with that metal component - the shaft has extra play and it starts.

The noise goes away with the diff engaged because the other side starts turning, and takes the load off the drivers side CV on the roller bearing... mine did the same - engage the diff, noise stopped immediately (different bearing design on the passenger side shaft)

Anyway - the solid bushing worked for me thats for sure. Its been pretty cold in these parts this winter so it would have been moaning away for damn sure. Some people have said the bushing cured their steering wheel vibe at that magic highway entry speed but I can't say I've ever had that issue regularly. Thats another thing that comes and goes ever so slightly and only with the stock tires and ambient temps. Never on my soft Michelin snows, so who knows...

Good info, thanks for sharing!

FWIW, I also think steering wheel vibe at highway speed is unrelated to this bearing issue as you mention. That's more likely down to tire uniformity and balance. I have absolutely no vibrations with my Falken Wildpeaks, but I did have a little bit with my stock tires for the first thousand miles or so until they eventually smoothed out. I assume they got flatspotted sitting on the dealer lot during the early parts of the COVID stuff...

 

[mountainbiker42]

Well for whatever reason, my needle bearing came apart. The noise/humming returned only a few thousand miles after having the first differential replaced.

I want them to replace the entire front diff and CV axle. I've been using 4 wheel drive lately with the snow in Colorado, so there a chance a piece of metal could have gone through the gear mesh.

I hope you guys are right that 2020 had a redesigned diff, maybe I got an old part. The dealer I use is pretty pathetic, I want to call them out by name on this forum but I won't.

 

[mountainbiker42]

Interesting. So you're saying you had a slight noise for the duration of your warranty that didn't really get significantly worse, and that then you had the bearing replaced it wasn't totally destroyed? I wonder if in some cases like yours, the bearing isn't totally failed, just noisy.

I also still don't totally understand why this noise goes away when in 4hi. The left CV shaft rotates the same speed whether the vehicle is in 2hi or 4hi, it's just that the front driveshaft is engaged when in 4hi. But as I understand it, the bearing that is the culprit is the left side output shaft/CV bearing.

I imagine the noise goes away because when you put the vehicle in 4hi, it puts torsional force on the CV axle. This force is probably enough to calm the CV vibration inside the needle bearing. Just my guess.

 

[Crocket]

Can't say that I had the issue off the lot new (summer 2017), but it certainly came into play over the first winter as temps dipped below zero I could hear the groaning, I chalked it up to the bridgestone duellers - perhaps a bad belt. 2018 winter, same noises but seemed to come and go. 2019 winter I became aware of the TSB and since I bought snow tires it certainly wasn't the factory tires now - with the info I was reading I decided to try the dealer (twice) and of course, they never heard anything LoL., so that didn't leave me with any confidence I wanted them tearing into my front end either. Fortunately I have a local off road shop who worked up my Jeep TJ for many years, also very familiar with Toyota trucks in the same sense and were obviously very familiar with this annoyance. They don't use the ECS bearing they use one from Nitro Gear, exact same thing. Anyway - I waited for my warranty to expire and had that tapped in there with the fluid changed out, left the factory seal in (oil was nice and clear - no issues presented even though I thought the groaning was getting louder this past fall), has been smooth and quiet since... so I would recommend to anyone to have that bearing replaced it seems to be a simple process for any mechanic, took my guy an hour... the entire differential assembly isn't the problem I don't know why Toyota is doing that repair - perhaps to avoid recognizing the actual design fault?

Good to hear there's a local shop familiar with the problem. Would you be able to share their name/number, as my 2017 has the same problem. Dealer already replaced the front needle bearing once, but it only lasted a year before the noise came back.

 

[17KT4R]

Good to hear there's a local shop familiar with the problem. Would you be able to share their name/number, as my 2017 has the same problem. Dealer already replaced the front needle bearing once, but it only lasted a year before the noise came back.

Well its going to get warm out soon so it should go away! :roll::roll:

Sounds like you might want to consider the same option then. CT Motorsports, across from the Airport at 7050 Bramalea Rd. Typically best to drop by when you're in the area and speak to 'Ski', owner, I typically see him very busy & getting to the phone is a challenge ! Cheers...

 

[mountainbiker42]

If you've been following this thread, I have a pretty interesting twist ending.

I took the vehicle into our local dealership with the metal pieces that were stuck to the drain plug. The service manager said since this is a repeat failure, they were going to call a Toyota Field Rep who would immediately deny warranty because of the 1.5" lift. My only option was to return the vehicle to stock.

I decided to take this thing apart for a second time and inspect the CV shaft and bearing for myself. Let me remind you the entire front diff was replaced shortly after buying it for the TSB needle bearing issue.

I pulled the CV shaft out and found an ECGS bushing sitting right there inside the diff, in perfect condition along with the CV shaft. The dealer has no paperwork showing this was installed, and no one can tell me where it came from. If the dealership replaced the entire front diff and installed this ECGS bushing, where in the world did these needle bearing pieces on the drain plug come from? I had no clue what to do at this point. I put everything back together, cleaned the magnetic drain plug, and drove to get pizza. I don't know where the cyclical rumbling is coming from. I guess I'll wait for something to grenade and check the magnetic diff plug in a year or so?

This diagram from the parts department shows a needle bearing on each CV (passenger and drive), but I was under the impression only the drivers side had a needle bearing. The needle bearings are call-out 41331G. If this diagram is right, then each side has one?

 

[Jeremy556]

Crazy.

My guess as to what happened: Diff housing was not replaced. Tech was familiar with the issue and instead of replacing the housing and bearing they just installed an ECGS bushing, and during removal of the bearing they managed to damage it to the point they lost some of the rollers inside the housing without noticing (ie they had rollers all over the floor of their bay and assumed they all made it to the floor).

Perhaps the casting or machining of your diff housing is far enough off that even with the bushing there is enough play to cause the sound, or maybe the axle shaft is a few thousands smaller than it should be, or it could be something else completely. Did you say the noise goes away in 4wd?

As far as the bearings being on both sides - yes, they are on each side of the carrier, however on the passenger side, the CV doesn't go into the carrier. There is an intermediate shaft (41304F) that runs from the carrier through the tube (part 41320) and that shaft is supported on the other side by another bearing (part 41304L), so it is near enough to perfectly straight with no side loading of any kind.

 

[mountainbiker42]

Crazy.

My guess as to what happened: Diff housing was not replaced. Tech was familiar with the issue and instead of replacing the housing and bearing they just installed an ECGS bushing, and during removal of the bearing they managed to damage it to the point they lost some of the rollers inside the housing without noticing (ie they had rollers all over the floor of their bay and assumed they all made it to the floor).

Perhaps the casting or machining of your diff housing is far enough off that even with the bushing there is enough play to cause the sound, or maybe the axle shaft is a few thousands smaller than it should be, or it could be something else completely. Did you say the noise goes away in 4wd?

As far as the bearings being on both sides - yes, they are on each side of the carrier, however on the passenger side, the CV doesn't go into the carrier. There is an intermediate shaft (41304F) that runs from the carrier through the tube (part 41320) and that shaft is supported on the other side by another bearing (part 41304L), so it is near enough to perfectly straight with no side loading of any kind.

Yes the noise goes away in 4 wheel drive. The symptoms exactly mimic the TSB for driver side needle bearing issues.

I did some deep diving into how the front diff ADD 4 wheel drive system works. I learned that when you’re in 2 wheel drive the spider gears inside the front diff are spinning constantly. This could be the source of the issue too, hard to tell. If that drivers side needle bearing comes apart, it doesn’t look like there’s an easy path to the bottom of the diff housing.

I’m moving out of state in a month. I’m halfway tempted to reinstall the factory suspension (which I kept), and say hey look what fell out of my differential. This whole situation smells.