Would you worry about this oil seepage from the 4Runner rear differential?

[mom]

When my 4Runner was being aligned, I snapped this photo of apparent (minor?) seepage from the rear differential.

I have read about the seals, but this looks like it's leaking from a different spot (nowhere near the brakes). I had the rear brakes off recently and they were clean of oil.
- Advice requested for adjusting parking brake for rear drums

Where should I look closer to identify the source of this leakage?

 

[ToyTec Lifts]

It is pretty common to leak a small amount like that. It is most likely coming from either the Pinion seal or the 3rd member seal itself. I would clean it off and see where/if it comes back.

:cheers:

 

[JWaldz]

If you just had the fluid changed out it's common for it to leak for a little afterwards.

Like stated above, just clean and see if it comes back.

You're rear axle is throwing me for a loop though.. Where is your fill plug?? Looks funny.

 

[mom]

If you just had the fluid changed out it's common for it to leak for a little afterwards.

I never had the differential fluid changed.

clean and see if it comes back.

Thanks. That's what I will do.

Where is your fill plug?

I have no idea. From this diagram, it looks to be near the top on the drivers side.

 

[blizz86]

I never had the differential fluid changed.



Thanks. That's what I will do.



I have no idea. From this diagram, it looks to be near the top on the drivers side.

I believe thats your breather plug.. the picture was just at an awkward angle with the line bracket covering the fill plug... its usually in the rear facing side of the differential in the middle a bit to the right.


part 42110a

 

[JWaldz]

I believe thats your breather plug.. the picture was just at an awkward angle with the line bracket covering the fill plug... its usually in the rear facing side of the differential in the middle a bit to the right.


part 42110a

You're right with that being the breather plug as well as the angle of the picture. The back of our diffs have a hump that sticks out and combined with the angle and the ebrake bracket, it's just hiding.

 

[nevada]

its probably the pinion seal. and the oil is blowing back and up onto the housing.

its hard to tell in that pic, but it looks like the forward portion of the diff is wet.
which would mean pinion seal. fairly common actually.

 

[mom]

its probably the pinion seal

Having never heard of a pinion seal, I looked it up.
- Toyota 4Runner parts lookup engines

Apparently a clogged breather causes pressure to build up, which blows out the pinion seal, so both should be replaced at the same time.
Obvious question: Where is the "pressure" coming from in a differential?
Another question: Is the breather the part highlighted in red in the previous diagram?

I couldn't find any pictorial DIY, but here's a text-only R&R DIY for the pinion seal:
- Pinion seal leak fixed! (MINI WRITE UP TOO) - YotaTech Forums

EDIT: I found a pictorial DIY How NOT to replace a pinion seal

Here are some non-pictorial threads discussing leaking 4Runner pinion seals:
- Secrets to removing differential pinion seals
- Yotatech pinion seal & clogged breather
- Yotatech pinion seal
- Rear differential pinion seal leaking

Looking at the Toyota parts diagrams, there's nothing called a pinion seal:
Q2: Is the pinion seal this part highlighted in red below?
41201C, 9031138047, SEAL TYPE T OIL

 

[Kung]

Hi mom!

 

[98Roamer]

You're missing a spare tire.

:becky:

 

[gannonrt]

"Apparently a clogged breather causes pressure to build up, which blows out the pinion seal, so both should be replaced at the same time.
Obvious question: Where is the "pressure" coming from in a differential?
Another question: Is the breather the part highlighted in red in the previous diagram?"

The diff pressure builds up under heavy loads. That could be towing, really hot days and lots of cargo or some off road situations. That's why the breather is installed. It allows the air in the top half of the diff to expand and escape. People will extend that breather to prevent water from entering during water crossing when the hot diff hits cool water and the air is sucked in.

The red part is the diff breather.

 

[mom]

missing a spare tire.

Actually the bad camber wore out the front tire so I was driving on the spare, but the alignment shop wanted the same wheels, so we put the spare) tire on the front for the alignment and then swapped it back out after the alignment.

BTW, here's a shot from just now showing the previously hidden plug:

 

[mom]

the breather ... allows the air in the top half of the diff to expand and escape.

I see. Thanks for taking the time to explain for a fellow 4runner owner!
I crawled under just now and the 'gunk' appears to be dry, and very tarlike.
I could scrape it with my fingernail.

It does seem to be coming from the other side of the differential:

The red part is the diff breather.

Thanks for the confirmation. What I should do is buy a pinion seal, and remove and replace the breather valve.

 

[quicksilvr]

Replacing that pinion seal seems like a waste of time and money to me. Unless it's dripping on your garage floor every night, let it ride another 50k miles....

 

[Dous]

Yea a huge waste of time. Quite a bit of labor involved.

And the PS on these axles is much beefier than the axle seals. I would expect one of them to start leaking long before the PS

 

[Stick Figure]

I'll agree with leave it alone, only I will add throw some fresh fluid in it if your still on old crap fluid. A new fluid of the proper weight could help your leak disappear. Even if it doesn't fix it this isn't a quick easy DIY project.

 

[nevada]

Replacing that pinion seal seems like a waste of time and money to me. Unless it's dripping on your garage floor every night, let it ride another 50k miles....

Yea a huge waste of time. Quite a bit of labor involved.

And the PS on these axles is much beefier than the axle seals. I would expect one of them to start leaking long before the PS

what? its MAYBE an hour labor tops.
i could do it in 20 minutes.

pull the driveline, remove the pinion nut, yoke and seal. replace seal. reinstall in reverse order. the only thing, you have to worry about is overtightening the nut. but, unless you TRY to overtighten it, that wont happen.

ive seen MANY MANY rearends burned up due to a leaky pinion seal.

just have it fixed.