When I bought my '85 4Runner, the PO told me that he always unlocked the front hubs for driving over about 50mp. He said if you didn't, the front diff would "burp some gear oil."

I wasn't really sure what he meant, but I headed his advice, even though it was inconvenient. In my old Trooper, I would lock the hubs when snow came and pretty much leave them locked all winter. never had a problem.

So after some local, muddy, class IV road scouting on Sunday, I forgot to unlock the hubs again. I didn't realize this until after I drove to and from work, on the highway, on Monday. :pat:

I could smell gear oil, so I popped under the front and sure enough, there was gear oil on the top and side of the diff that came out of the breather.

It wasn't much, and I'll make sure it's full before I run it again.

Now my question.. is this normal? Other then making sure it's topped up, can this cause any harm? Why does this happen?

I'd appreciate any input... thanks.

 

My '85 will squeeze oil out of the knuckles when the breather's clogged but never out of the breather. That's a strange one. Noone's been topping off the axle through the breather have they? If you use the fill plug, the axle should only be about 1/3 full of oil. The diff case will sling it around when the hubs are locked but it shouldn't be coming out through the breather. Is the breather complete with cap? I don't know, that's a tough one. I've never had that happen.

Eric

 

Definitely not overfilled. I recently changed it over to AMSOIL and it is filled to level with the fill plug.

The breather is a bit dirty, but not overly so... the "cap' thingy is still loose and moves easily.

I've got the parts to do the extended breathers and I'm doing them next week.

It's a riddle.

 

Is it the stock diff? The toyota diffs I've seen have splash guards inside the diff case to prevent the oil from sloshing out the breather. I suppose it is possible that someone took these off to fit a custom third member?

 

I'm positive it is the original diff.

I would have to guess that the breather is plugged and that the gas builds up enough to the point that it finally blows past the clog, taking some oil with it.

I'll put on my extended breathers next week and hopefully it won't be an issue again.

Thanks guys.