sneakysnake

Hi all, I'm normally just a thread "stalker" looking at threads and such and learning. But I couldn't find anything with the search to help me out; so here I am.


1994 4runner v6 4wd
Onto my dilemma, I have a leak somewhere in my rear axle. Its causing the back center of my axle to become covered in oil, now up until earlier this week that was it, just moisture, no drops or anything. I look under on tuesday evening and notice a drop forming on the bottom most point of the axle and a point where some had already leaked onto the ground. So, I pulled out my haynes manual to find out what probable causes are. I've got it narrowed down to the pinion oil seal, does that sound correct? And if it does sound right, could someone please give me a quick run down on how to get it taken care of. The manual has a long list of steps and the way its written has always confused me.


So if yall could take some time and help me out, I would very much appreciate it.




Andrew

bigt

prolly the diff drain or fill flog or like mine the nuts around the diff.. i snapped one when i pout my welded rear in and it drips a little every day... next time i take the axle apart i will fix it with nuts instead of studs

JCM4x89pu

..it's an easy fix..
..buy a new oil seal at autozone, and drain the diff oil.. then you unbolt the driveshaft flange from the pinion flange (i think it's called the companion flange or something).. then mark where the big nut in the center is (so you can torque it down properly later, and not ruin your diff by over or under tightening the pinion bearing.. check the preloading specs in your manual).. then pull out the companion flange, and pry out the old oil seal with a pair of pliers.. or by whatever means necesarry (pry bar, screw driver, slide hammer, etc.) then tap the new one into place, and seat it down into position using the companion flange as a tool.. then slide the companion flange back in, and snug up the pinion nut.. then you preload the nut to the specs in your manual (it should turn right back to the matchmark you made earlier) ..and finally, bolt the driveshaft flange and companion flange together... and of course, refill your diff with good gear oil.

Crawdad

This is the procedure in a nutshell - it's not a hard fix. Though, I would try your best to make sure that the pinion seal is indeed the culprit. I would recommend going to Autozone or even Walmart and getting some degreaser (Fast Orange, Purple Power, Green Lightning, whatever.) and cleaning the whole diff real well, with a brush. Let it dry, and before you drive it, see where the oil is coming from. There are a number of places at the rear diff that fluid could be leaking from:

Pinion seal
Drain plug
Fill plug
Third member/housing mating surface (ie - leak in the seal)
Loose stud or nut
Rear ABS sensor, if equipped

When you drive, the oil gets blown all over the place. It can be deceiving.

sneakysnake

Crawdad: thanks, I will definately do that first.

JCM4x89: Thanks, that makes it seem a lot easier than the book portrays it.


Will report with my findings.

rustypigeon

Before you do anything else make sure that the air vent on the top is clear. My differential was leaking from the pinion seal and it turned out to be a clogged air vent. I unplugged it then degreased the axle to make sure there were no more leaks. Problem solved.

sneakysnake

So, I cleaned off the rear axle so that I could tell for sure where the oil was coming from. And it wasn't the pinion oil seal, its coming from that contraption in the pictures. The guy at advance auto said that it is my differential cover, he said that I need a new one.

thoughts?

86tuning

are you losing brake fluid?

Toyota diff covers are part of the housing.

clean it up with brake cleaner and check for further leakage.

rustypigeon

almost looks like the brake line is cracked underneath the bracket. Is your brake fluid low? brakes spongy? You will be able to tell by the smell. Brake fluid and gear oil have very distictive smells. GL5 gear oil has a strong sulfur odor, while brake fluid smells like... well, brake fluid.

sneakysnake

Its still leaking, but I'm not sure if its brake fluid. I don't know what brake fluid looks like. The fluid coming out has the consistency of oil and looks like very clean motor oil.

I havn't noticed any brake fade.

rustypigeon

check your brake fluid reservoir under the hood. The level should be a bit low if its been leaking like that for a while.

awdjunkies

I had both(Pinion seal & the brake line) mine replaced as a precaution and it seemed to have solved the problem... Looking at those pictures, mine looked worse therefor could not tell which one was leaking.

JCM4x89pu

yep, looks like brake fluid.. all good advice so far... you can be sure, because brake fluid should be water soluble, and therefore will wash away with water... diff oil won't.
may need a new brake line.. might as well clean/replace your diff. breather while you're at it. if it is in fact the brake line, we'll let you know the right way to replace it and bleed your brakes.

as was mentioned.. the first thing you should do is check the level of the brake fluid in the reservior on top of your master cylinder ASAP, and fill it to the max line.. don't want you to lose braking ability and fly off the road!

Lysmachia

Well Brake fluid is not only water soluble but highly corrosive and not to mention toxic. By the rust on your flange bolt to the rear diff looks like your rear brake hard line needs a little love!!!

What does that mean? Well get some "hard" break line and a mini tube bender. It will be a hell of a lot cheaper for you to remold the break-line than to have a mechanic do it. (PM me with ??'s)
**************

If it is NOT the break line (And you should prolly do this any-way!) then as "vatozone" says it could be your diff cover, though I HIGHLY doubt it. If you rule out the brake line then here is what you do next.

1) Drain the rear diff. You have a bolt on the bottom of your rear 3rd member. Prolly a size 22. DON'T strip it. Or you'll cry. Make sure you have the right size and lo-sen it. Make sure you have an oil drain pan because a whole-;lotta diff oil is gonna come out (Like 3 quarts.) Ideally it would be red, or purple or even black. If it is milky grey... well then you needed to change it any-way (mean you got water in your diff).

Drain away. Then in tha' mean-time order a couple of new drain plugs from Toyota. They are all the same size and work for your transmission too so get like 3. Get the inverted Allen wrench kind with magnet embedded so if you wheel hard in the future you can tell if you have a problem with your ring and pinion (more on that later).

If you HAVE to take apart your rear diff... well then you need a new seal. Either that or RTV it. From your pics you should NOT need to do this. If you think you do, PM me.

OK. You have DRAINED THE DIFF! Whoooo. Hoo! Now ya need at least 3 to 4 quarts of good gear oil. TC and I used to use Redline but if ya have an ARB in there (You don't) it is too thick. Royal purple or Amsoil should be fine. Put the new diff drain plug in (remember those... the one's with magnets and an Allen bolt locking key??. And fill away/

How do you do that sideways? Good question. Some funnels and matching tubing usually works. Maybe some-one will chime in with a better method (suction pump).

Now remove the Diff "fill plug" again same type so ya might want to replace with an Allen bolt plug. Here is where you re-fill with the 3/ 4 or so quarts of gear oil. Re-fill till it starts to leak out. Don't over-fill (not like you can....)

Again you really should do this if your diff oil is in ANY way milky. That means you got water in there. And for future reference to NOT get water in there SEARCH on diff Breather Mod. You need to do this before you go driving in deep water...

Kinda like this:



Good luck!

And YT crew, feel free to correct me if I got any of this wrong!

OH Crap. Forgot to tell you how to make your diff seal better. Well.. if it isn't your brake line Post up. You'll need to remove the diff cover and then put a gasket in there, even if it is a "liquid" gasked like RTV.... Gotta do THIS before you re-fill with any diff oil (as I instruct above!)

Lysmachia

Oh... and at the VERY end you sould prolly install DIFF breathers to avoid milky water logged diff oil in the future. (like below suggestion!)

sneakysnake

Alright, so I'm still not positive as to whether or not its brake fluid thats leaking(as the guys I usually ask to help me are out of town currently), however I checked my brake fluid resevoir and it is completely full up. So I doubt its that, because I'm starting to lose oil at a more rapid pace, and I figure I would have seen a drop in brake fluid by now, right?




So now what I should do is change the diff oil; is that right?

dirtoyboy

Well, changing the oil wont fix the leak will it?

The only thing I can think of is that maybe there is a hole under that brake line bracket and when the truck runs it slings gear oil up into it....

You need to confirm what type of fluid you are leaking.

sneakysnake

Alright, I spent a while this evening and really cleaned the rear axle good, scrubbing off the layers of crap that had built up. I also checked the brake line that runs over the axle there, its in quite good shape, so I'm quite positive that its not the brakes leaking.

However, I did notice that my breather was very much overwhelmed with mud, I cleared that out and drove around for a while and could not get it to leak for me. So is it possible that the breather being clogged caused my problem?

If that was the problem and I don't notice any more leaking I'm still planning on changing that rear axle oil when I get a chance this week, and ordering the parts necessary for the breather mod so that I can get that done in the next week or two.

Crawdad

Yeah. When the fluid and air inside the diff heats up, it expands, creating positive pressure inside the differential housing. Normally this is exhausted out the breather tube, but if the tube is clogged, then it will force its way out wherever it can - usually the pinion seal is the easiest place.

sneakysnake

I'm 95% sure that it isn't the pinion oil seal now, as there is absolutely no oil around the pinion oil seal. After unclogging the breather last night and driving for a longer distance this morning the leak came back. It looks like its coming from under that brake mount that is welded onto the rear diff cover. I've examined the brake cable and its in great condition for its age. I'm going to find out exactly what kind of oil it is that is coming out tonight.

Is it possible that my breather has gone bad? Or that I've gotten dirt or something clogged up in there that I can't get out.