Rear Differential Leak -- Check Your Rear Diffs

[M40A1]

I have a 2024 TRD Sport, born on 16 Feb 2024 at the Guanajuato plant (3TY VIN). Took delivery of it this past March and noticed the last few days some oil spots on my driveway. I took a good look underneath the vehicle this morning and, sure enough, the bottom of the rear diff was wet. From the pictures below you'll note that the leak is coming from the fill cap on the back and then seeping down to the bottom. Note that my driveway is on an incline (not that this is an excuse, just that when parked I'm sure the diff oil is above the fill cap). While I am sure the fix is as easy as tightening the cap, I decided instead to drop it off at the dealership and let them properly square it away, hopefully I'll have it back early in the week...

Anyway, purpose of this post is to document for you my issue and to advise you to keep an eye on your rear diffs for any leaks.

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20 June 2024 Update

I received a call from the service advisor this evening, he said that they have an open case with Toyota on the leak issue. The dealership provided pictures to Toyota and, according to the service adviser, the leak is coming from the weldment where the female threaded insert for the plug was welded into the rear of the case (Look closely at the weld at around the eight o'clock position of the 3rd picture from the top, there appears to be a gap in the weld. Not 100% sure this is the spot, but it looks suspicious). The service adviser says that they are going to replace the "rear cover," and that this part may take awhile to get delivered. You'll also wonder like me, there is no replaceable "rear cover," the cover is welded to the rear axle housing. Regardless, my guess is that the entire rear axle assembly will likely get replaced. I'll update this post once the issue is resolved.

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[Captain O]

Thank you for the great post! I will go look at it right now, as my truck is same vintage as yours.

cheers,
PO

 

[TacoFreak]

Looking forward to hearing what your dealer says about the leak and what they did to fix it.

 

[jdr]

3TY owner here, just about 600mi or so.

Just got back from checking my rear diff. Marks on my driveway always throw me off because my previous car used to leak so much oil... I've left leak marks in my garage, my driveway, and at least the 1st four visitor parking spots up front...

Fortunately though, my diff is dry, no leaks so far. I even removed the cardboard covers skid plates up the front of the truck to check the front diff too.

OP, thank you for posting your PSA! Let us know how it turns out.

 

[TrustButVerify]

I have a 2024 TRD Sport, born on 16 Feb 2024 at the Guanajuato plant (3TY VIN). Took delivery of it this past March and noticed the last few days some oil spots on my driveway. I took a good look underneath the vehicle this morning and, sure enough, the bottom of the rear diff was wet. From the pictures below you'll note that the leak is coming from the fill cap on the back and then seeping down to the bottom. Note that my driveway is on an incline (not that this is an excuse, just that when parked I'm sure the diff oil is above the fill cap). While I am sure the fix is as easy as tightening the cap, I decided instead to drop it off at the dealership and let them properly square it away, hopefully I'll have it back early in the week...

Anyway, purpose of this post is to document for you my issue and to advise you to keep an eye on your rear diffs for any leaks.

I think that's wise. It creates a paper trail of defects. Had you been parking in a greasy parking garage, this could have gone unnoticed until it was too late. While this is minor, the other option is to file a NHTSA complaint since this is a safety concern that would seriously imperil you had you been on a long road trip or driven the vehicle home from a dealership out of state:

Report a Vehicle Safety Problem, Equipment Issue | NHTSA

 

[M40A1]

I updated the original post...

 

[TacoFreak]

@M40A1 Thanks for the update.

That is one nasty weld where the plug insert is welded into the rear diff cover, even if that is not the cause of the leak. That is not something I would expect to see in a Toyota truck.

I look forward to hearing that it is finally fixed. Are you still able to drive your truck while you wait?

 

[M40A1]

@M40A1 Thanks for the update.

That is one nasty weld where the plug insert is welded into the rear diff cover, even if that is not the cause of the leak. That is not something I would expect to see in a Toyota truck.

I look forward to hearing that it is finally fixed. Are you still able to drive your truck while you wait?

Great question! Yes, the service adviser said that the mechanic can put some sealant around it as a temporary fix until the "part(s)" come in, which could take some time given a new model. I told him that once he gets a status on parts to call me back and we can decide then if I should come and grab it until they can make the repairs.

 

[rchrds]

Oh man. The list of things to look at on pickup is building up. Thanks for the heads up on the update.

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