Rear differential leaking tons of fluid

Numbers look good.
But did you get 4 quarts out?

 

Good points

 

I do not see how you could have caused any pinion seal leak. You did say this was the first time you drove it on the highway so I'm assuming you drove very slow during the break in period so this could be why it didn't leak or at least not much to notice before. The faster you drive the more oil gets thrown forward by the ring gear.

You need to check the level and fill then take it back to the shop. They messed up the seal.

Did they use a new Toyota seal?

 

I’m betting it’s the pinion seal.
Almost has to be, when the axle seals it slings oil in the fender wells.
But you’ll usually see it puddled by the back tire, or smell it first.

Pinion seal slings it just like the photo you posted.

 

What does the breather look like?

 

Well, we can rule that out then. Normally with an overfilled diff, the oil will come out the breather before it blows the pinion or axle seals from too much pressure inside the diff. So that’s more evidence that it was not caused by overfilling/too much pressure, and likely a bad pinion seal as many have said. Take that thing back to the shop. If the gears look ok and they don’t redo the setup, I’d definitely ask for an extended warranty from them on parts and labor since this already happened so soon.

 

I'm no expert here but I had a sort-of similar experience at Premier west gears about a year ago. Had polished gears installed so no break in really but the shop suggested at least some initial mild break in on my 100 mile trip home. I got out every so many miles to let the gears cool and I inspected underneath and had no issues. Of course, by the time I got home, I had a spray pattern very much like yours, really everywhere but particularly where the pinion seal was. I had to drive it all the way back the next day and they changed the pinion seals and I haven't had any issues since (except for being very perturbed). So similar to yours, I didn't see the spray right away but it developed a bit later.

 

No. I went back and measured. I used one of those oil pans that doubles as a container. I poured all that would come out reasonably fast and got to 2.8 quarts. Even if I let it sit and drain over night I would not have gotten up to 4. I didn't fill the dif until the drain hole was done dripping so I know I got everything out I reasonable could.

 

Perhaps the shop did not replace the seal when then popped it apart. Sometimes this works and sometimes this is what you get. Grab the correct OEM seal and bring her back. She'll get another low mileage fluid change and a new seal. Heck if it was my taco I would slip the guy a $ 20. And remind him to do it right. I know some guys here will balk at this. I do give to the guy doing the work, not the service writer.

 

Did you ever figure out the cause? We are dealing with the exact same issue except our gears were change 5-6000 miles ago. 2023 24,600 miles

 

The OP post almost one year ago. Your case is last year. Is the breather tube for your rear diff clear, not plugged up? One of the causes seals can blow.