Front axle rebuild ? Use gear oil ?

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Ashphalt Rulz!

I pissed in my knuckles last time I rebuilt them. You need one of those flexi funnels. It only leaks when I go over speedbumps. Be careful, drinking to much beer can lower the viscosity...
 
Okay, first lets get a few things straight:

When a Toyota Engineer (or any manufacturer) SPECIFIES a particular type of lube for a particular bearing or 'joint', he/she doesn't choose by rock/paper/sissors. They didn't put gear oil into the differentials and grease into the knuckles just so auto part stores would have to stock more stuff.... What goes on at the microscopic level in different types of 'joints' is very different and this leads to different types of lubricant.

Grease (and not just the cheap stuff, but molybdenum disulphide) is used in a birfield because of the high pressures involved. Not that the axle housing is pressurized, but the six little ball bearing get forced into the birfield create high pressures due to their small contact patches. The GREASE is used because it can withstand these high pressures without breaking down (at the molecular level) and losing it lubrication properties.

Gear oil is used in differentials because of the inherant design of the Hyploid gears. As well as creating contact points where the gear teeth mesh, the ring and pinion teeth also slide past one another with a shearing action. This shearing is why hyploid is specified. Cheap oil can't withstand these shear forces and will break down.

The long and short of it is:
Yes, both oil and grease are slippery, and both bearings and gears need lube, but to say they are interchangeable is simply not correct.



Now to address your case:

You say your mechanic thinks it will work. I have to agree that sometimes all it takes is a little thinking outside the box. However, don't you think that with all the issues brought up by people here, you're justifying doing something without really applying sound knowledge. Hey, lets face it, most 20+ year old toyota knucles will weep an oil/grease mixture akin to oatmeal. But, once cleaned and replaced with new parts, they will be trouble free for many years. END OF STORY!

They leak due to being old and not maintained, however, they're not poorly designed. Why not fix the problem at hand and not have to deal with all the fiddly issues that crop up (yearly knuckle rebuilds with new wipers, weeping hubs, 'drips', etc) much less depriving your birfields of the correct lubrication they need. Also, the lube that the birfields need is between the ball bearings and the bell. The 2 lbs. of grease between the bell and the knuckle housing doesn't do anything for the birfield-bell-to-ball-bearing wear surface (we put it in there to catch busted shards, suspend dirt and metal away from the contact points, and so when you turn, the birfield doesn't squeeze out its grease). To address your birfields lack-of-grease issues, they need to be disassembled periodically (more that once in 20 years) and grease packed INTO the birfield bell. Filling the knuckle housing via the plug does NOTHING for the internals of your birfields. Putting gear oil into your knuckles does get lube into your birfield, but it doesn't do what it's supposed to when it gets there.


I understand your open-mindedness regarding this as an experiment, so why don't you send your oil out to get analysed when you do a fluid change. I'd be interested to know what the condition of the gear oil was, and also the amount of metal particles in it. Some before and after pictures (1000+ kilometer swith the hubs locked or off-road) of the wear surfaces on the inside of your birfield bells might be interesting and educational.

Cheers,
Steve
 
Steve,

Good points. Couple follow up comments.

Mechanic is ASE Certified 1989 in Solid Front Axle Repair. So far ~ 30 miles off road(novice terrain) and ~ 6k miles road. Slightly damp on the rubber 'O' ring seal of the drivers side hub(still original factory 'O' ring). Probably have loss about 1 oz. through this seal. Other than that, no drips, no runs, no errors ... Nothing, not even on the driveway where I park every night either.

The Cruiser front axle does specify grease, however this front axle is not unique to Cruisers. As some one stated before there may be 200,000 Cruisers with grease in their knuckles running around ... but guess what ? There are probably over 2 million other non-Cruiser vehicles running around with the same front axle using gear oil.

Didn't think to get inner pictures of the Birf bells when open. Oil analysis sounds intriguing. Didn't use cheap gear oil either, went with Pennzoil 75w-90 Long Life Gear Oil. It's mineral based but has Pennzoil's proprietary molecular structure for enhanced viscosity performance(what ever that is worth).

As 'dd113' stated ... "serves no real purpose except your desire to make it work."

So far so good with gear oil in my knuckles & Birfs,
Cahil
 
I know toyota uses closed knuckles, and someone pointed out that a few older Dana axles also used closed knuckles, but the vast majority of domestic trucks use open knuckles (u-joints exposed to the air). Off the top of my head, older MOG axles (404's, not sure about others) use gear oil in the portal boxes, but the CV joint is housed in an open knuckle. What axles are you referring to that are 2 million strong with closed knuckles? Just curious, not trying to be fickle.

Cheers,
Steve
 
I haven't seen this addressed, how are the upper knuckle bearings being lubed? Do you think there is enough gear oil splashing around in the knuckles to keep the upper bearings properly lubed? These may be the first parts to begin to fail, which would lead to a looseness of the knuckles, and probably leakage at the seals on the back of the knuckles.
 
lubrication in axles

Like was said last, mogs have their cv joints exposed. However, pinzgauers do not and they are lubricated by gear oil like cahil is trying to do here. I don't see why everyone cares if he is trying this or not. Older american vehicles with closed knuckles often used hypoid gear oil instead of grease. Most folks pack them with grease when they leaked. I would suspect that if you asked Dennis at Linden engineering he would think that the gear oil would lubricate the birfields better than grease. Before some a****** states that Toyota never designs anything wrong then read my post again and notice that I am not saying that grease wouldn't work just fine for millions of miles. But, Toyota didn't design the only 4x4 on the planet and Landcruisers are not the cure for cancer. No offense intended to the Landcruiser but I have spent more time and money on my FJ60 than any 4x4 I have ever owned including mogs and pinzgauers. I still love it though.
 
quoted from 75pinz:
"Before some a****** states that Toyota never designs anything wrong then read my post again and notice that I am not saying that grease wouldn't work just fine for millions of miles."

Whoa 75pinz, nobody's calling anyone an a******. We're just having an objective discussion.

Yes, Toyota has made some muck-ups over the years, but all in all, I think their engineering knowledge is sound. Nothing is ever perfect. BTW, what earlier post are you referring to?

If this works, well power to cahilc. He's tried applying something different to his cruiser. I'm not saying I'm for or against this, It's just that I (This is my personal opinion now) don't feel it offers ME a significant improvement over my current grease. However it's nowhere near proven itself with only a few miles of 'testing'. If it is going to be considered a success, it's going to have to equal 'greased' birfield lubrication, and not leak for a number of years (even after swapping birfields).
 
smcruisin said:
...
Just curious, not trying to be fickle.
Click to expand...

Not fickle at all.

Most of the domestic vehicles of the same vintage, Dodge, Ford, & Chevy have front axles almost identical to the Cruiser. I saw one on an old Dodge truck which pratically looked swapable for the front axle under my Cruiser.

Don't be fooled into thinking that Toyota designed the front axle under our trucks, improved it - maybe, installed Japanese bearings, seals, and gears - definitely.

But originally designed it, nope, noway ...

Cahil
 
Godwin said:
...
I haven't seen this addressed, how are the upper knuckle bearings being lubed? Do you think there is enough gear oil splashing around in the knuckles to keep the upper bearings properly lubed?
...
Click to expand...

Knuckles were re-assembled with grease, then filled throught the top fill plug with one heck of a lot of gear oil. Some where around 2 - 3 quarts of gear oil ? Freakin' lot of it.

Yup, upper knuckels should be fine with all the splashing around of oil.

What people have missed is that the wheel bearings are also running on gear oil.

:D

Cahil
 
I'm sceptical. First of all I don't see any benefits. Birfs can't be lubed through the square bung on the top of the knuckle. They need to be removed and filled with grease about once a decade if you don't wheel your rig and every time you break one if you do.

That being said, if this is something that turns your crank, go for it. You won't do any harm except to make a mess of your drive way eventially. Frankly I'm surprised it lasted a week. My junk blows tube seals fairly regularly and I end up with 80-90 on the inside of my tires all the time.
 
let me clarify.

I am skeptical that it won't leak over the long haul. I am also not going to bother with experiments like this as grease works fine. But, I suspect the gear oil is better for a lot of reasons as far as actual lubrication goes. That being said, who cares? The grease works fine. But, Toyota front axles are similar to many older Dana axles. Notice that they quit making them and went to the exposed Ujoint. Not because the exposed ujoint is better. Because it is cheaper and easier to service and works fine for 99 percent of the people. My 74 F250 has a HD D44 that has a similarly designed axle. I have heard it is not as strong as far as joints go because they are smaller than the later exposed joints. That being said, it has a big V8 in it and has never given a problem in some terrible abuse. But, the Toyotas have a bigger axle and no power. Toyotas seem overbuilt in a lot of ways. I like that.
 
One more thing to think about.

I suspect that fill plug is for grease put there by Mr. Toyota himself. We all know grease won't get in the birfield if we use this hole. Is that a design flaw...? Unless I am wrong about the hole's intended use...Which could happen.
 
a holes or lack thereof

And I didn't mean any offense by the a****** thing. I just figured somebody would flame me for stating that toyota didn't design the first 4x4 and maybe others had some good ideas. Sometimes it is hard to have discussions like this on a brand specific board. best regards, bryan
 
75pinz said:
I suspect that fill plug is for grease put there by Mr. Toyota himself. We all know grease won't get in the birfield if we use this hole. Is that a design flaw...? Unless I am wrong about the hole's intended use...Which could happen.
Click to expand...

From what I've seen the fill plug is *identical* in size, place , location to other vehicles(domestic) which use gear oil in their knuckels.

I would assume the fill plug was in the original design of the axle and Toyota left it there for simplicity ?

Just my best guess,
Cahil
 
This is hillarious. Cahilc's disillusion appears to be fueled by proven points of reason backed up by not only the manufacturer but millions of people who BTDT. He's yanking eveyone's chain.
 
So what ever happened with the gear oil? Did I miss the results in a seperate thread?
 
So since you are running this in the wheel bearings too when you spring a leak your screwed as your wheel bearings will lock up! Unfortunately I've done more axle rebuilds than I care to have done. This method would never last in an 80 series. I'd probably be leaking by the end of the driveway.

Have you ever thought that all of these companies that used to run gear lube in their closed knuckles went to open knuckles for a reason? Maybe they couldn't get the seals to stay sealed for long periods of time.

If you wanted to make it really easy to drain and fill why not just leave the axle seals out? Then you could drain at the diff and fill at the knuckles.
 
thanks for pulling this up kurt. it was around before i got here and a great read. and now i too want to hear how it worked out
 
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