Front Diff Grinding/Groaning Cyclical Noise
- Thread starter MikeYQM
- Start date
RichinRidgewood
New member
If they changed the part number they changed something.
If they didn’t change the pn and changed something then they might end up in the same boat as GM and their ignition lock problem.
I specifically use this as an example of how not to do design work when coaching Junior Engineers.
They changed the pn?
Just to add to the "successes" list... Had my ECGS bushing installed this evening and BAM driving home is a like a whole new truck. I don't think I realized how annoying and prevalent the hum/groan was until it is no longer there.
That being said, the ECGS tool's threaded rod was absurdly short for me, like only a few threads through the plate, and not enough to grab the rod and keep tension on it. Luckily we happened to have a much longer rod w/ the same thread pitch (intended for BMW RTAB's I think) that worked wonderfully
That being said, the ECGS tool's threaded rod was absurdly short for me, like only a few threads through the plate, and not enough to grab the rod and keep tension on it. Luckily we happened to have a much longer rod w/ the same thread pitch (intended for BMW RTAB's I think) that worked wonderfully
Blackdog99
New member
But still there is the issue that we are having (TWO) issues during this discussion about the front diff/Carrier issue. The one nobody is talking about is the failure to "fully" disengage the 4WD at the T-case. So, it keeps the front driveshaft slowly spinning, which causes the noise from the problematic carrier.
Jetboy
New member
This is the only information I've seen:
"Some 2016-2019 Toyota 4Runner 4WD vehicles may exhibit a cyclical groaning/grinding noise from the front differential in 2WD that is not present in 4WD operation.
If the condition is confirmed, remove the front differential and install the new/revised front differential. A production change occurred at the Tahara factory starting with VIN JTEBU5JR#K5632980.
The previous front differential part number is 41110-35A91. The new part number is 41110-35A92."
That's a quote from Mitchell1 auto repair software.
Blackdog99
New member
That's not what I'm referring to. I know because we have Auto hubs, that causes the "axle shafts" to spin. I'm referring to the Driveshaft (Some call this a prop shaft) from the Transfer case to the front diff, is not fully disengaging.
When you switch from 4WD to 2WD, it should disengage and stop spinning the front driveshaft.
Your prop shaft is connected to a spinning wheel
Jetboy
New member
That's not quite how it works.
The transfer case uses a dog clutch to disengage the front shaft. It is no longer directly mechanically driven. The front axle shaft on the driver's side will spin the spider gear that will then rotate against the other spider gears internally. Most of the rotating is balanced by the free spinning counter rotation on the other side of the spider gears as they are disconnected. However - friction between the spider gears will always apply some rotational moment to the carrier assembly. It then causes the carrier to spin slowly and that pushes the ring gear and slowly spins the pinion and the front drive shaft.
And that's a good thing. It keeps all the bearings lubricated and coated in gear oil.
Even in trucks with manual hubs that disconnect - the same thing happens. The front shaft will still spin slowly.
It should have no effect on this vibration issue.
As an update Toyota did replace the front Diff with part number 41110-35A92. Let's hope this will last longer than the last one.
NauticalSR517
New member
Late update but I finally got my truck back after the fix and everything went great. Dropped the truck at the dealer Monday afternoon after work and picked it up Tuesday afternoon. No noises or vibrations thankfully, it drives just like new! The service girl said it took about 5 hours altogether and that was the remove/install and test drive plus a wash and vacuum of the interior.
Thank you to everyone on here for the links to TSB's and sharing the initial issues. I drove myself crazy trying to figure it out before I found this thread!
Thank you to everyone on here for the links to TSB's and sharing the initial issues. I drove myself crazy trying to figure it out before I found this thread!
Blackdog99
New member
Has anyone been through a diff swap under the TSB at a good dealer in the Boston area?
Fourrunnershawn
New member
Update on mine....dealer drove it and acknowledged the noises again. They are putting me in a loaner tomorrow and keeping it until it’s fixed. I showed them this thread and what the culprit seems to be. They have not given me any hint of what they are going to do. We shall see.
Mass 4runner
New member
My 2019 started doing this at about 27K. Took it into the dealer this morning, showed them the tsb, and they've ordered a new differential. I was shocked at how easy this was, as I was fully expecting the usual "no problem found" result.
Mass 4runner
New member
It's not done yet but I just got back from Acton Toyota of Littleton where I showed them the tsb and they have ordered a new diff.
Blackdog99
New member
Thanks Mass 4runner! If I call, anyone I should speak with there?
