Front Diff Grinding/Groaning Cyclical Noise

[RichinRidgewood]

...the earlier IFS models, the ones with manual hubs had a machined carrier assembly that didn't even have a bushing. Just some oiling grooves in the machined carrier. So the bearing has existed (and been an issue) since literally the first IFS toyota built and they've never re-designed it.

I think at a minimum, if you wanted a bushing instead of a bearing, the aftermarket bushing should be an oil grove bushing. That was one of my concerns in my post about the "solid bushing".

The failure mode is when the shaft has so much play in the needle bearing that it wobbles when spun and thus the "hum" or "groan" ??

 

[Jetboy]

I think at a minimum, if you wanted a bushing instead of a bearing, the aftermarket bushing should be an oil grove bushing. That was one of my concerns in my post about the "solid bushing".

The failure mode is when the shaft has so much play in the needle bearing that it wobbles when spun and thus the "hum" or "groan" ??

The thing is - there's always a ton of play. It's not a tight fit at all even when new. I don't think it has anything to do with wear on the bearing or the shaft. It's just a loose tolerance fit. I'd bet that the seal does more to stabilize the shaft than the bearing most of the time.

The bushing from ECGS is not like a machined oil film bushing. They are IIRC a PTFE impregnated bushing. So they don't necessarily rely on the gear lube for lubrication. The brass is porous and acts like a sponge where the PTFE plastic lubricant is absorbed into the pores. As it heats up it will weep out the plastic lubricant, and as it cools - it gets absorbed back into the bushing. Functionally it works a lot like wheel bearing grease rather than oil. It may be an oil impregnated, I'm don't remember. Either way, it's designed so that it's not required to flow gear oil through the bushing for lubrication even though it probably does use gear oil as the primary film of lubrication unless it ever ends up run dry and then it would weep.

Edit: I just double checked and ECGS has changed the bushing entirely to a new model. The new one is simply a PTFE bushing. No brass at all. Just literally a plastic bushing. No oil necessary.

I think it would be better to have some oil passages. I'm sure you could machine them if you wanted or order one with some oil flow machining. My concern would be that the oil passages wouldn't be large enough to do any good with thick cold gear oil. Typically they're deeper than the entire thickness of these bushings when they're used for heavier weight oils that are unpressurized.

I suspect that's why both ECGS and most or all aftermarket differential carriers use an impregnated bushing instead of one machined for gear oil flow.

 

[Krayziekid]

Damn, you're getting a whole new dif? I just got the bushing replaced lol

Yea I was really shocked by that too, but the TSB now says 2017 and up (I think) should get a new diff instead of just the bearing replacement. They couldn't tel me if anything was new with the diff haha but if the TSB has been updated to replace it, I have to imagine it was for a reason. Definitely going to be keeping an eye on it to see if it was a permanent fix. Will report back.

 

[97BlackAckCL]

Yea I was really shocked by that too, but the TSB now says 2017 and up (I think) should get a new diff instead of just the bearing replacement. They couldn't tel me if anything was new with the diff haha but if the TSB has been updated to replace it, I have to imagine it was for a reason. Definitely going to be keeping an eye on it to see if it was a permanent fix. Will report back.

Probably easier to just drop and swap it out then disassemble and swap the bearing out

 

[Blackdog99]

Still looking to see if anyone has thoughts on why the shaft is still spinning while in 2wd. My mechanic said the actuator that moves the fork back n forth is likely not fully retracting, thus the slow rotation of the front shaft.
Mine is a '14 sr5

 

[RichinRidgewood]

... I just double checked and ECGS has changed the bushing entirely to a new model. The new one is simply a PTFE bushing. No brass at all. Just literally a plastic bushing. No oil necessary...

A plastic bushing as a replacement for a steel roller bearing. facepalm

 

[dedonderosa]

can someone post or take a video of the actually noise? is it more a grinding noise or kind of like tire noise? or like a wheel bearing noise? i really dont hear anything except for my shitty terra grapplers that are starting to cup.

 

[Anand]

can someone post or take a video of the actually noise? is it more a grinding noise or kind of like tire noise? or like a wheel bearing noise? i really dont hear anything except for my shitty terra grapplers that are starting to cup.

More like very specific wheel bearing/tire noise... By very specific I mean at only a very exacting range of speeds, temperatures, and easy to pinpoint that it is the driver's front only

 

[Krayziekid]

Ok this might be a very stupid question lol, but I'm assuming diffs have a break-in period of some kind?

I had my diff replaced and I haven't been able to drive the 4Runner much until today. When getting up on to the highway, things just felt slow and dragging for some reason. Like, I had to press harder on the gas to get up to speed and when I left off, it feels like it decelerates much more quickly than it normally does. Think this has something to do with the new diff? It's a really odd feeling that I didn't feel like I had before the new diff.

Or should I try pulling the neg terminal to reset the ECU and see what happens?

 

[Fourrunnershawn]

Add me to the list. 2019 SR5 with 1800 miles on it. Noticed the hum/droning noise within the first 300 miles. Took it to the dealer and they blamed it on tire flat spots because it had been sitting on the lot too long(pure bullsheet)(they got the car in 4/19 and I didn’t purchase until 12/19).

I get the noise between 30-40mph. I also get steering shake between 60-70mph. Totally unacceptable.

I approached them with the TSB and they said my runner was just out of the date range....but they did acknowledge the noise and steering shake.

They said put about 1500 miles on the tires and it’ll solve itself(pure bullsheet again) but I entertained their request. That was at 600 miles...at 1800 now and the problem still persists.

I plan on taking it in Monday. I’ll keep y’all posted.

 

[dedonderosa]

More like very specific wheel bearing/tire noise... By very specific I mean at only a very exacting range of speeds, temperatures, and easy to pinpoint that it is the driver's front only

only thing i hear is my shitty nitto terra grapplers with 21k miles. no change in tone between 30-40 mph when switching into 4wd

 

[Jetboy]

Ok this might be a very stupid question lol, but I'm assuming diffs have a break-in period of some kind?

I had my diff replaced and I haven't been able to drive the 4Runner much until today. When getting up on to the highway, things just felt slow and dragging for some reason. Like, I had to press harder on the gas to get up to speed and when I left off, it feels like it decelerates much more quickly than it normally does. Think this has something to do with the new diff? It's a really odd feeling that I didn't feel like I had before the new diff.

Or should I try pulling the neg terminal to reset the ECU and see what happens?

Yes - diffs do have some break in time. Front diffs like ours are really never probably broken in like you would in a rear diff. The only parts spinning in 2hi are the spider gears. Could have some period to wear in the spider gear tooth mesh, but probably not much. More resistance could also be from a re-fill with heavier gear lube. But it shouldn't be very noticeable in most cases. I'd watch your mpg for a while and see how it compares to what you had before. There should be very little friction in 2wd. In 4wd, the problem bearing isn't spinning. In 4wd there will be a break in period for all of the differential bearings. The ones that spin in 4wd are much larger heavier duty bearings and you'll also have some wear break in on the ring/pinion gearset.

 

[arehman11]

Ok this might be a very stupid question lol, but I'm assuming diffs have a break-in period of some kind?

I had my diff replaced and I haven't been able to drive the 4Runner much until today. When getting up on to the highway, things just felt slow and dragging for some reason. Like, I had to press harder on the gas to get up to speed and when I left off, it feels like it decelerates much more quickly than it normally does. Think this has something to do with the new diff? It's a really odd feeling that I didn't feel like I had before the new diff.

Or should I try pulling the neg terminal to reset the ECU and see what happens?

I’m feeling a similar effect after my new diff. I’m going into the dealer Thursday for this and that the noise has started to come back and the vibration too. It drove great for about a thousand miles and then this happens.

 

[Krayziekid]

I’m feeling a similar effect after my new diff. I’m going into the dealer Thursday for this and that the noise has started to come back and the vibration too. It drove great for about a thousand miles and then this happens.

Report back with what they say and if that feeling goes away! I am planning on swinging back by my dealer if it doesn't go away after I put some miles on it.

 

[dweh54]

My 2017 is in the dealer right now getting this repaired. 26k now. I first noticed it a year ago and it is more pronounced when cold.

Dealer first blamed it on the tires (said they were cupped) but I snagged the Falken ATW3 when they were marked down a few weeks back so that took that reason out for the dealer.

The sweet spot is right at 42 mph and I waited for a colder winter day to bring it in to demonstrate. I had to make a few trips to the dealer but a senior tech rode with me and he heard it. The hum would be about every 3 seconds lasting about 1 second per. Then placed it 4wd, and the hum was gone.

 

[VBRover]

2019 w/35K started a few thousand miles ago.
I had to take it to the dealer twice for the tech to hear/feel the issue (it seems they like blaming everything on cupping tires) As others have stated, happens when cold (-2F here), between 38-45 mph, and goes away engaging 4WD. They will be replacing the DIFF, 3-5 days wait on part.

 

[NauticalSR517]

Well I finally got the call this morning that the new diff was at the dealer and ready for me to bring the truck in. I went in Jan 21st and they said eta on the new diff would be Jan 30th. Just a bit late but I'm ok with it seeing its under warranty and I pay nothing. I scheduled a drop off for Monday after work and hopefully pick it up Tuesday afternoon with no noise!

Funny the last few posts mentioned cupping. When I took mine in initially the tech heard the noise but the service girl also mentioned cupping on the tires after he was done. Thankfully I used the TSB and this dealership had a few others with the same issue from the last year. I'm waiting for them to try and sell me new tires when I pick it up lol.

 

[Jetboy]

What's incredibly frustrating is that Mike Sweers, the head of Toyota's truck division, claimed recently that this isn't a real thing. I guess he's trying to bring Chrysler quality to Toyota.

 

[catrains]

Add me to the list. 2019 SR5 with 1800 miles on it. Noticed the hum/droning noise within the first 300 miles. Took it to the dealer and they blamed it on tire flat spots because it had been sitting on the lot too long(pure bullsheet)(they got the car in 4/19 and I didn’t purchase until 12/19).

I get the noise between 30-40mph. I also get steering shake between 60-70mph. Totally unacceptable.

I approached them with the TSB and they said my runner was just out of the date range....but they did acknowledge the noise and steering shake.

They said put about 1500 miles on the tires and it’ll solve itself(pure bullsheet again) but I entertained their request. That was at 600 miles...at 1800 now and the problem still persists.

I plan on taking it in Monday. I’ll keep y’all posted.

2019 runner no warranty ? not gonna fix it ?
post the dealerships name location .. go to another dealership .

could be tires need a balancing or the brakes are binding .. drive it a few miles and check for all the rotors on how hot they are.. should be the same temp..

they should also check the drive train fluids.. also grease the drive shafts.

 

[Matt831]

Has anyone been able to find what exactly is different/re-designed in their replacement diff?

Since it looks like there are a few owners outside the TSB vin range...later model 2019s that have this noise and I would assume an updated design as well from the factory.

Mine comes and goes, but most noticeable when below freezing, can not hear it when the temp is above 45F or so.