Gearbox leaking into Transfer - 2000 RZN169r DC

[blackmo92]

Hi All,

I recently purchased a RZN169r Hilux that has done about 190k kms, I purchased a Haynes workshop manual which in combination with this forum has been very useful to give it the TLC it deserves! I have also discovered ToyoDIY and Amayama which have been a real eye opener on parts availability and pricing (the mark up here is AUS is sometimes 40% more than Japan / UAE!! I imagine it is probably just as bad in SA).

Decided to do a pretty standard service on it:
- Changed oil / oil filter (genuine)
- Changed fuel filter (genuine)
- Changed air filter (genuine)
- Greased the squeaky speed cable
- Replaced rear diff oil

After the diff I decided to do the transfer case and to my surprise oil flowed out of the fill plug. I screwed it back in and checked the gearbox and sure enough it was about 100ml low (approximately how much came out of the fill plug. Its so typical that doing this PM has actually unveiled a bigger problem.

There seems to be a few opinions on how to tackle this,
1 - Leave it as is and check transfer oil periodically (i.e. 2 months) drain TFC and top up gearbox.
2 - Use a breather hose pipe (connect to both fill plugs)
3 - Replace cheap seal inside case. (my preferred choice)

Looking at the workshop manual this looks like a big job even though the parts are dirt cheap (input shaft seal, front output shaft seal, selector shaft seal). Unfortunately I have checked a few independent mechanics and all of them are unwilling to touch it / claim it will require an entire gearbox breakdown / rebuild. I have a mechanically minded friend who has an array of jacks / tools etc. so we are considering doing this over a weekend but before we go into it I would appreciate any advice / guides or opinions on how best to tackle this!

Should I change all three seals at once?
Is there anything else I should consider doing at the same time?


As for the rest of the car, I unearthed a few other gremlins when I took off the bash plate
1 - Looks like the crankcase pulley has a leak (not dripping just looks dark)
2 - The driver side CV / Diff seal looks dark too (perhaps a leak)

Apologies for the incorrect terminology, this is my first foray into the mechanics of a car / maintenance


Appreciate any advice

[pampoen]

Well I would definitely interested in this because it looks like I will prob be doing the same very soon, especially if I want to get the vehicle through road worthy legally.

[Mars]

My approach is always that if I am going to do all the work to remove the transfer case then I would replace all the seals, regardless of whether the others are leaking or not. Remember that the other seals have also done 195 000 ks. If it is required to remove the gearbox entirely then I would also remove the clutch and flywheel and replace the crankshaft oil seal as well. I also have a great problem having to pay a premium for genuine parts but as far as oil seals are concerned I only buy the Toyota seals. I can get an after market crankshaft seal for literally 10% of what the agents charge but I am prepared to pay a premium if it means I won't need to redo all the work soon.

The front crankshaft oil seal should not be too much of a hassle to replace either. Basically you remove the crankshaft pulley and wedge out the old seal with a screw driver or a specialist tool designed for the job. Just make sure that you don't scratch the seal housing (for the want of a better word) i.e. the surface where the outer part of the seal makes contact and seals. It is normally a cover/housing made of aluminium.

It can be quite a struggle to get the bolt off that holds the crankshaft pulley in place. It is also important to put oil on the threads of the bolt and to make sure that it is tightened to the correct torque setting. One should also apply some oil on the inner lips of the oil seal to ensure that it slides over the edge of the step where it is supposed to form a seal, without damaging the new lips of the new seal.

I am actually not sure how much work it would be to remove the front drive shaft to be able to replace that seal. If it is not obviously leaking I would wipe that area clean and watch it over a period of time to see if it actually needs to be replaced. Having said that I firmly believe that prevention is better than cure.

[Mud Dog]

I see that Marius has posted while I was busy compiling my reply, but I'll post mine un-amended in case I cover an issue that he hasn't but also to confirm those he has.

If you do it then replace all 3 seals at the same time. Also check the play on the gear lever - if you pull on it up / outwards (it's spring loaded) it should move by 5 to 8 mm at the most - more than that and the nylon bush that the "hajf ball" of the lever seats against needs to be replaced. Also if the lever is "floppy" then the pin through the turret that secures the lever is worn or the pin has worn the turret. That will need to be addressed and you might need to employ the services of an engineering works since the pin is not available as a spare part on it's own (you have to get the complete lever assembly, and it's pricey). There are some threads here on the forum relating to this and some guys have made their own repairs.

The seal kit might be cheap as chips but the job is a tedious one - although I've never done it, I think the guys you have already approached are correct in saying that the gearbox has to be split to fit the seals as I would imagine that they are fitted from the inside of the casing ends. I would also fit new X-fer box seals on both the rear and front output shafts while it's apart. It might just be prudent to have it done by a professional gearbox & diff centre.

Of course the whole box will have to come out to do the job, so while it's out I would replace the clutch, release bearing and pilot bearing (AKA spigot bearing). At the same time I would check the condition of the pressure plate and flywheel - pressure plate may need to be replaced and flywheel skimmed. Also examine the ring gear on the flywheel (the starter engages against this) - it might be in need of replacement as well. Then I would also replace the rear crank seal in any event at the same time while everything is out - cheap and easy job but if you have to do it later you have to drop the box again and that's a mission.

If you want to go a step further, I would also check the prop-shaft centre bearing (AKA carrier bearing), but this is easy enough to replace later if you have to.

Good luck.

[blackmo92]

Thanks for the comprehensive responses, I totally agree with replacing any easily accessible seal while its all out.

I have contacted a mechanic / part yard that specialises in only Hilux's who advised the cost to replace the inner seal is about $400AUD ($4,205.70ZAR) which I think is quite reasonable, I imagine the bulk of the cost would be the labour to remove / reinstall gearbox / tfc so replacing the additional seals will hopefully be marginally more expensive.

Can anyone advise if the transfer overhaul kit contains front and rear transfer case output shaft seals and everything that is required for the TFC?
Similarly I have looked up the rear seal part number but if anyone can advise if anything additional is required I would be very appreciative.

TRANSFER ASSEMBLY & GASKET KIT - GASKET KIT, TRANSFER OVERHAUL - 04362-35061
SEAL, ENGINE REAR OIL - 90311-88003

I will look into the clutch, what is the consensus on aftermarket vs. genuine clutch kits? i'd imagine quite a few $$$

Thanks again everyone

[Mud Dog]

To the best of my knowledge, like most auto manufacturers, Toyota outsources their clutch plates to producers like Sachs and Luk Repco. Both are of course available in spares outlets, usually at a lesser price than through a dealership. You can't go wrong with either brand.

[pampoen]

So I took both boxes out myself and sent it to the local gearbox centre R1800 for all seals and to reseal where the box had been leaking in the middle. Way less hassle and stress and they even pickup and deliver.

[Mud Dog]

[Mars]

That's the way to do it. And now you will have peace of mind when driving in your bakkie.