Transfer Box Oil Leak

[porky Lurker Find all posts View Profile Close porky]

Hi Guys, I have a 98 Prado auto which I have owned for 6 years. The other day I noticed a patch of oil on the ground and have
since discovered a leak from the transfer box. Is the prop shaft seal easy to change or do I send it in to the experts? I guess the seal has gone due to the lack of engaging 4wd lately, and it is 12 years old and done 190,000 kms. Any help would be greatly appreciated.

Cheers Dan

[Chriso57 Senior Member Find all posts View Profile Close Chriso57]

Re: Transfer Box Oil Leak

Dan,

None of the seals are all that hard to change under there, providing you have the following:
- all the right tools
- the time to do it
- the mechanical know how to get it apart, inspect for worn parts, and get it back together withouut causing further problems...

I am a mechanic by trade (although I no longer fix stuff for a living) and without trying to sound negative, if you need to ask then you probably should get the experts involved. Might cost you $100-200 for them to do it or it could cost you a transfer case if you dont get the seal in right...

[porky Lurker Find all posts View Profile Close porky]

Re: Transfer Box Oil Leak

Thanks Chriso57, I will put it in to be fixed, that's what the PM was about.

Porky

[luked Member Find all posts View Profile Close luked]

Re: Transfer Box Oil Leak

Aha... knew someone would have had this same seal go..

Recently fitted gearbox and transfer case breathers before going on a decent drive.. (being in Sydney not that often it gets to operating temperature) and oil started leaking out of the same seal in my 98, 100,000kms.. first drop of oil its ever dropped... checked oil levels and changed breathers around for some larger hose and hasn't leaked since... (Yes it still has oil in it!!) hasn't been on a long trip but either..

A "guy" told me that they (toyotas) commonly pump gearbox oil into the transfer case when hot creating extra pressure and case the transfer case to leak but the oil returns when cold... and reckoned that replacing the old seal for new seal will make it hold for another 12 years.. but they need a double lipped seal between the gearbox and transfer to proper fix it....

but this "guy" was driving a Nissan :roll:

[luked Member Find all posts View Profile Close luked]

Re: Transfer Box Oil Leak

Ok feeling like it's time to return something to the forum hee, spoken to a few people that have had this seal go, seems as it sits low and faces forwards it is one of the first.. I had a crack at it the other night and seems to have solved it, test run was on Sunday with Glenn and Jeff. Unfortunately the hands got a bit greasy so a couple of photos are missing but you can probably work it out pretty easily from what I got here.

What ya need

The seal from Toyota (Transfer case output shaft seal) I was quoted $20.20 over the phone but got charged about $15 when the guy recognised me down there.. you know how it works..

A 30MM SOCKET AND DRIVE OR POSSIBLY A 30MM RING SPANNER TO ACCESS THE RECESSED NUT ON THE OUTPUT SHAFT FLANGE

Ya standard set of sockets spanners and screw driver

Its always easier to work in a clean environment so try clean the area up the best you can at each stage of the disassembly.

Think 12mm bolts on bash plate


Now drain the oil out the back while you keep pulling the front apart


Think 14mm on drive shaft flange (NOTE THE RED CROSS!!)

Now the bolt is actually splined so you won't turn it, turn the nut only... but pretty hard to tell until you get it out..
Once you loosen the bolts they are still quite tight due to the spline so you need to put the nut on level with the top of the bolt before hitting with a hammer. This protects the thread from damage. You will have to raise the front axle of the car or at least oonce wheel to allow you to freely rotate the driveshaft to access all the bolts.


Now mark which hole lines up with what so you can put it back together the same way...


Now there is a picture missing as my hands got filthy and I forgot when putting it back but you can now see the end of this shaft with the big 30mm nut on it. Now is the time to clean up the area the best you can as once the flange comes off the transfer case is open for nasty stuff to fall inside.The nut has a section which is bashed into the keyway to stop it from rattling undone. You need to hit it with a centre punch to open it up and allow the nut to be undone without binding on the keyway. You can see the keyway on the below photo which is once the nut and flange are taken off. You will need to grab another beer for this bit and try not to think about how you should have taken it to a mechanic (as i did). ALSO "try" and mark on the inside of the flanged section and the shaft BEFORE you pull the flange off as it is best to put it back on the spline in the same place.. I may have failed this one.. but a scribe or your centre punch will probably scratch a line across the two that you can line up later during assembly. To stop the flange from turning I put a screw driver through one of the holes in the flange and turned the 30mm nut until the screw driver jammed against the transfer case.


Once you get here my manual says to drill a hole into the seal and then insert a screw into it and put the seal out.. I didn't feel comfortable about drilling and making shavings with my transfer case open so I simply got a (CLEAN) big flat screw driver and levered the seal out. The seal came out quite easy, yes i bent it but it all came out in once piece which I preferred. You do have to be a bit careful to make sure you don't score the area which the seal sits in as this will become a place for oil to leak out.


Once the seal is out again clean up! being careful not to have grit and stuff end up in the transfer case..

Now examine the sealing surface on the back of the flange which contacts the rubber seal. Mine had a line around it where the steel had worn from the abrasion against the rubber seal however it was only very slight.

IMPORTANT: wipe some oil onto the inside surface of the seal as if you don't it may have quite a bit of friction for your first few kms and it might heat up and damage it..

Installing the seal is done alot more precisely than the screwdriver removal method. Getting a socket or something similar is the best method and tapping the seal in with a hammer gently. I Couldn't find anything that nice for the job so actually used a piece of 10mm thick flat bar and just tapped it around the edges evenly.

Once you are happy with the installation of the seal put it all back together how it was...when I put mine back together I found I got the 30mm about the width of the key way tighter than what it was on before so the mushed up section of the nut didn't line up anymore. I just hit the different section of the nut back into the key way. I sleep better at night knowing it is now at least as tight as it was before. Wipe it all clean and keep an eye on it over the next few days or trips as you might not know before it's too late if your transfer case dumps all its oil.

Wow this turned into quite a long description but I have tried not to miss anything important. Hopefully if someone has this fault this will give them a bit more confidence about what is involved. The whole job only took about 2 beers.. but I had quite good access under the car. Some pictures are missing but I have described the process. If your not sure about doing the job I am sure that it's cheaper to pay a mechanic to do the seal than to have them rebuild the whole transfer case if the seal isn't installed properly.

[MikeyB Member Find all posts View Profile Close MikeyB]

Im doing this job today. Im following this very useful thread, ive run into a problem on mine that i thought i sho.uld add to this thread so anyone else preparing for this job knows what they could be up against.

[MikeyB Member Find all posts View Profile Close MikeyB]

Actually i think i should write up a new thread instead of hijacking this one.
Heres the link
http://www.pradopoint.com/showthread...575#post469575