Both rear axle seals are leakings on my 3rd gen 4runner ~180 000. Driver side is leaking worse. (oil on tires) I'm pretty bummed, but I'm trying to stay positive by informing myself:

1) If the breather is the culprit (I suspect this because both seals are leaking), can I just replace the breather, top off the oil, and expect to have normal seals again? Or once they are leaking they are done?

2) Can I drive it to my mechanic's garage in this state? I have no idea how much oil is in there, but I'm assuming all the oil can't all leak out of the seals as part of the diff sits lower? I have no leaks in the pumpkin.

3) What are the correct seal part numbers for 3rd gen 4runner? I read that Toyota has improved them at some point, so if I have to replace them I'd like to use the new version

4) I'd like to put in an extended breather eventually, i notice that some people just use the stock breather part on the end, while others use a fuel filter to get 2-way operation. It seems that the later makes more sense, especially for a situation where the diff cools quickly, opinions?

5) I suspect it's been leaking for awhile... I've probably put a few hundred miles on it. Could I have caused some irrepairable damage?

 

Rear axel seal replacement Bible this link should have all the info you need and more.

 

Thanks for the link Diesel Dog, it definitely answered some of my questions.

I'd still like to eliminate the possibility that the seals are still good. If I can put in a new diff breather myself and run it for another year, that would seriously help my finances. Is there any possibility my seals have some life left in them?

 

I don't think so. From what I've read once the oil is pushed thru the bearings it's only a matter of time before they fail. If its a minor leak you might get by with just a breather, but my guess is once the seals are gone they are gone.

The cheap fix would be to replace the seals and breather and run it that way, but there is no telling when everything will fail again.

If your handy you can do the repair yourself. I followed the directions in the link above, it wasn't too bad of a job.

 

The breather allows pressure to escape due to heat being produced in the diff. If the breather is clogged, the heat needs another way to escape, which is through the axle seals. As you can imagine, this destroys the seals. Which is why the seals are letting fluid get past.

 

Like that makes any sense at all.

Save yourself the headache of trying to imagine the false conclusion that hypothesis leads to.

Yes, the seals could still be perfectly functional. If the breather is clogged. Since the leaks might not be caused by, or resulting from, wear on the radial lips of the seals.

BTW, most of us here still find the use of the term "T4R" to be mega-annoying. Whoever started that one ought to be shot.

 

Hypothesis? I'm not a scientist. A clogged breather causes seal failure. He states "both rear axle seals are leaking."

He's got fluid leaking. After opening up all of the drum to diagnose the problem, wouldnt it be great to have these inexpensive new seals on standby?

Sure I don't see any problem in just replacing the breather. The rear brakes will be much less effective soaked in fluid. And you may be unsure if just replacing the breather did anything at all, unless this is a severe leak. Than again a severe leak would be even a bigger issue than just some maybe possibly bad seals. See what I'm getting at?

 

At 180k miles its time to replace it all anyway. Dont just put a bandaid on it and hope it goes away. And don't be cheap and cut corners. The oil that escaped the diff has washed out the bearing lube. The bearings are now shot. Tear it down and refresh the seals and bearing. Now that link above has good info. I started a thread which explains why new seals fail. You'll have to search for it under my name though. I'm too lazy to repost it.

It took me three times doing it the way it was posted in that thread above before I figured it out on the fourth attempt. It's been 14,000 miles of leak free driving ever since.

Good luck to you. If you don't plan to do it yourself, take it to dealership or to someone who specializes in 4runner/tacoma axle seals. The average mechanic won't be able to figure it out. By the time you are done, they will have convinced you that your axle is bent and you whole diff needs to be replaced. There are countless threads of ignorant mechanics duping people into expensive repairs because they can't get it right.

 

toyota supposedly has a updated redesigned rear axle and bearing to correct the flaws. might want to go that route although it will be pricey.

 

Anybody else having problems viewing the pictures in the rear axle replacement bible link?

http://www.toyota-4runner.org/3rd-ge...d-3rd-gen.html

They were showing up yesterday on my phone, work and home computer. should have made a pdf...

The toyota guy at my garage wasn't available today, but the owner told me they could do the job as long as the bearings weren't pressed on to the axle, hard to tell without the pics ). But the write up describes the bearings parts that go to the machine shop so I'm guessing I have to deal with another mechanic or find a machine shop.

As for the actual procedure:
I saw another thread where they described installing the retainer in reverse, to guarantee that the seal lip ends up on the shoulder. Which i understand would avoid the problems that many have experienced where the seal lip ends up riding on the bevel, and wears out quickly. Opinions on this?

 

This should maybe be in a new thread, but I found a nifty way to pull up websites that have had the pictures expire for whatever reason (wayback archive site):

Here is the axel replacement bible link, with the pictures intact:

http://web.archive.org/web/201205100...d-3rd-gen.html

 

Has anyone used the Marlin Rear Seal kit in their 3rd Gen 4runner?

http://www.marlincrawler.com/axle/re...ce-kit-1979-99

I have ABS, but i don't see any ABS rings in the kit and it's my understanding that I'll need to replace those when doing this job.

So what else would I need aside from the Marlin Kit + ABS ring? I was thinking of getting OEM inner seal as well.


It's currently on sale, and I'll likely be needing them in the spring. My seals stopped leaking when the weather got colder so i have more time to deal with this.

 

If you compare the oem seal with any other including the Ecoseal, what you will find is that the oem allows for move axle play than the others. The conclusion I came to was that the axle moves too much on the ABS axles and beats the heck out of the typical seal. The consensus is to only buy OEM parts.

 

Thanks for the quick feedback. I was thinking I would get the kit for everything except the inner seals, which I'd get from the dealer.

The OEM bearings are crazy expensive where I am, and from what I've been reading the Marlin bearings are good quality from Japan, just not the seals.

 

i know this is an old thread, but i don't think i want to go through the hassle of tearing this apart and taking it to a shop to press on and off. What do you think a dealer would charge for this?

I noticed today as i was replacing the rear springs and shocks and checked rear brake life, there was grease built up in there.

 

Well the dealer is going to be your most expensive option, that's for sure. I personally would never take my truck to the dealer. I just use an independent mechanic when there's something I don't want to do or can't do. I usually ask them to use OEM parts, from Toyota.

I know it varies and there is no one size fits all, but my experience with Toyota mechanics is that they aren't the best mechanics, and they'll charge insane amounts of money to often not even fix the problem.

Bringing a bearing to shop to press on & off isn't much of a hassle. But if I were going to have a shop do the whole job, I'd find an independent shop. I have a great relationship with mine.

 

One of the local stealerships who have done work before on our rig quoted $320. Others were higher, but this one has worked for us.

The problem with having these pressed in and out, you need to have a good shop that can be reliable if you are doing it yourself. I don't have that connection with a good shop and would rather not perform this service myself. i feel that there are a lot of things that could go wrong quick if not done properly.

 

Yes, that goes for all auto repairs. A lot could go wrong if not done properly. Any shop worth the space they take up should be able to do something like this no problem.

Anyway, obviously do what works for you.

 

On my 96 4Runner the shop I used didn't know the parts are spaced and not just pressed together. The resulting leak drove me nuts until we figured out what they'd done.
It was an easy mistake to make that would have saved some aggravation if they'd been paying attention.

As it should have been:

 

Well, ok then. I would expect shops to know, but there you go.