Recently did a couple trails in which i scraped and landed on rocks quite a bit, and went through some deep water crossings. Woke up the morning after to a pile of gear oil on my driveway with a leak coming out of the front of the diff where the driveshaft connects.

I checked the breather and it LOOKS ok, so i don't think it's clogged and causing over pressurization, so i think something happened with either the seal, or the rear pinion yoke. It drove home just fine and didn't feel too weird, so i don't think i dented the yoke. Maybe i just got some mud in the seal? What do you guys think my next steps should be? I linked a photo with the area that it's coming out of.

1991 LN130 Hilux Surf R150F G255

 

Top up the oil and see if it continues to leak. May.be you'll get lucky.

It is not necessary to disassemble to replace the seal, other than dropping the driveshaft and removing the yoke,

 

I drove it around a tiny bit and the oil seemed to stop leaking. Hopefully it fixed itself. I will top it off a bit more and see.

If i had to take it apart though, would the yoke come right out? Or are there weird clips i have to deal with?

 

Grego has a post on replacing the TRANSFER output seal. I believe differential seal would be about same amount of work. Not too daunting.

 

I’d drain the diff and make sure it’s not full of water. Maybe relocate the breather higher up if you plan more water crossings in the future.

 

So i ended up emptying it out, and it was filled with water. Was recommended that i flush it a couple times (After driving it a bit) and it should get most of the water out of there).

However, it started leaking again today after driving through some water. So im gonna do the diff breather extender mod and see if it happens again before i change the seal out.

 

Was the rear ok?

 

As in the diff itself? I didn't open it up, i just drained it and refilled it. I didn't hear any weird noises so im assuming its ok.

However when it was in the shop a couple weeks back for unrelated reasons, the tech mentioned something about the rear diff needing a rebuild sometime soon. Unsure what that was about but i guess ill find out when it eventually breaks lol

 

If you pulled the fill plug at the rear and excess oil/water didn’t pour out you were probably fine. But changing out the oil was a good idea. I’d move the breather on the rear, too.
rebuild needed? I’d ask the shop for specifics.

 

Currently planning on rigging up a diff breather extender.

Also the gear oil that came out was indistinguishable from chocolate milk. I'm told that when water and gear oil mixes it turns brown. After i extend the diff breather im gonna refill it one more time and hopefully she is good.

 

did you replace your pinion seal? I didn't see a post where you said if you did or not. its not exactly the same as the tcase output but close. the tcase output has a dust seal and a retainer and an oil seal. the pinion seal is a quick job. pull the driveshaft off, remove the 30mm nut on the pinion flange, pop the oil seal out (I use a screw driver and puncture the seal and pry it out gently, then I use a wood block to tap a new one in. marlin crawler sells a high quality seal, or oem is still an option. overpressure in an axle almost always blows out the seals at the wheels in my experience, not the pinion.

 

Agreed. I’d probably replace the inner axle seals at the rear as preventative. If they were compromised and start leaking it’ll take out the axle bearings.

 

No i did not touch the seals yet. After it started leaking the first time, i replaced the gear oil and it seemed to stop leaking so i assumed it was just a blowout. And after driving in some really cold water the other day i came home and it was dripping gear oil again, so i assumed i just sucked more water into the diff.

My current plan is to install the diff breather, replace the fluids, and see if it still leaks, then go from there.

Thanks for the help guys, I really appreciate it.