4x4 system lubricants?

[Scorpius68]

so i bled the brakes this weekend and found a hose that looked like it was loose so i moved it and welp...it broke off. It’s just a plain rubber hose and it went onto some stub coming out of the rear axle just left (drivers side) of the gearbox. What’s this for? And should the other end plug in somewhere?

Also...this got me to thinking. I’ve never messed with a 4x4 until now, so are there fluids i should check on the axles or elsewhere? How do i check them?

Only thing else i think to do for PM is perhaps pop off the tires and see if the bearings are greased up. Not sure though again 4x4...regular car it’s simple job. Any helps and pics or links helpful!

 

[Mbrooks420]

That’s a vent for the axle. It should just go up and away from the axle. Both axles have gear oil in them, and should be changed out. The transfer case has oil in it as well.

 

[92exp4x4]

The t-case uses automatic transmission fluid. Dex/Merc 3 is fine. There is a drain and fill plug on it. Just fill to bottom of plug hole.

The front axle oil must be suctioned out through the filler in the axle beam and gets filled to within a 1/4" of the hole. Same for the rear except you can pull the diff cover to drain it. If your vehicle is equipped with limited slip diffs, then you'll need to add friction modifier to the oil. 80w-90 is fine for both. Rear axle fill plug is on the pinion side of the axle, driver side.

Front wheel bearings are tapered roller and can be repacked. There is a roller bearing internal to the spindle that kinda guides the axle shaft through it. Significant disassembly is required to access it. You may just try to squirt some spray grease into it through the spindle. Rear axle wheel bearings run in gear oil and don't require any other service. You might pull the brake drums and check for seepage though.

The spindle nut keeper can be fun to remove if you have auto hubs. Make sure you have a pick and a small magnet. You'll see why when you get to that point. It's not hard, just a little confusing if you have not been into them before.

 

[92exp4x4]

Just thought also, check your u-joints for grease fittings while your under there. Some aftermarket joints had them. Also the slip yokes.

 

[RangerX]

If you have auto hubs, you can take them off, invert them, fill them with ATF, let them sit overnight, dump out the fluid and let them drip dry, and reinstall. Do not put grease in them.

 

[MrQ]

For the rear axle check the axle code on the door. If you have a limited slip rear diff it's 75w-140 with friction modifier. That's if it's a relatively low mileage unit, usually by this time the clutches are shot anyway and you can pretty much put anything in there. These 8.8 axles are remarkably strong...guess that's why Jeeper's use them. The D35 is also a fairly robust unit for its size. It's technically a third member and you would have to dismantle a good part of the front end to get it out and fully drain/clean it. Most people, as said above, just use one of those hand held vacuum pumps and suck the old oil out.

Make sure your breather tubes are in place and not broken. I have had my own personal horror stories of the wonderful things water can do to gear oil and bearings.

Check the front bearing retainer nuts and make sure they have not backed off. They are a common problem on these front ends. You can use the special tool for them and the by-the-book torque settings, but I just use a screwdriver and a hammer and adjust them by feel.

Good luck.

 

[Scorpius68]

For the rear axle check the axle code on the door. If you have a limited slip rear diff it's 75w-140 with friction modifier......

Good luck.

So my door shows the following (see pic) not sure what all the other codes mean.

41 Open 3200 3.27

 

[410Fortune]

If you have auto hubs, you can take them off, invert them, fill them with ATF, let them sit overnight, dump out the fluid and let them drip dry, and reinstall. Do not put grease in them.

You do this with manual hubs also, only difference is with the manuals you can click them in and out from "free" to "lock" about 50 times while holding them upright and full of atf. This will help dislodge any debris that gets stuck inside and lubericate the plastic internals....by the time you are done they will work like new again.
I let them drip dry for a LONG TIME like overnight so you do not water down your wheel bearing grease with atf

 

[Scorpius68]

If you have auto hubs, you can take them off, invert them, fill them with ATF, let them sit overnight, dump out the fluid and let them drip dry, and reinstall. Do not put grease in them.

You do this with manual hubs also, only difference is with the manuals you can click them in and out from "free" to "lock" about 50 times while holding them upright and full of atf. This will help dislodge any debris that gets stuck inside and lubericate the plastic internals....by the time you are done they will work like new again.
I let them drip dry for a LONG TIME like overnight so you do not water down your wheel bearing grease with atf

So i wonder....for my rifles and pistols i use a product called Kroil. It’s very good at penetrating an freeing stuff up and seems to embed itself into the metal for a good bit. I coat them in it and never worry about rust. Might work on these.

I think for now after checking some vids that i’ll Change out the lubes in the transfer case, the two axels. Will save the wheel bearings for whenever i need to do a brake job, but by then i may just simply replace the bearings.

Also question...4WD it feels really weird when you engage it and turn really sharp, almost like if you’re turning left, like the right wheel is getting pushed in the turn or something. Is this just a byproduct of 4wd on the street? It’s been years since i drove the humvees, of course those were in the grass or mud so i don’t recall that weird turn feel.

And i have the auto hubs so am i correct i can engage 4wd in forward or reverse at speeds below 55? How to i properly engage low gear? (Want to test it out)

 

[92exp4x4]

Kroil is the best! I love that stuff.

The part time t-case in the explorer will bind on dry pavement. It has no slippage at all. The Humvee, more than likely performed more like an AWD system.

The touch shift system is designed to engage up to 55 mph. There is an electro clutch in the t case that spins up the front driveline and locks the hubs through torque. Above 55 it may not be a smooth engagement.

Low gear is engaged by coming to a complete stop, going to neutral, then selecting 4x4. After the 4x4 light comes on, then hit low. It will then shift and the low light will come on. You can then put into drive and test low range.

When changing direction, the hubs will unlock and re lock. They work on torque being applied through the axle shaft. One very common failure is the u-joints in the axle shafts. If you feel a knocking or bumping in the front axle while the hubs are locked, you may have a u joint seizing up.

 

[Mbrooks420]

Don’t run 4wd on pavement.

 

[MrQ]

The touch shift system is designed to engage up to 55 mph. There is an electro clutch in the t case that spins up the front driveline and locks the hubs through torque. Above 55 it may not be a smooth engagement.

The electro-clutch is in the 4405 t-case. The 1354 in the first gens is purely mechanical, with the electric version just having a exterior electric motor to shift into 4x4. It uses synchros to match the road speed 1:1 when shifting into 4 high. 4 low has synchros, but it requires pressure to be taken off the transmission output shaft and next to no driveshaft rotation to engage (like pushing the clutch in on a manual transmission) When you engage 4 high, the front axle is engaged and when it turns it locks the cams in the auto hubs, like 92exp4x4 said. To disengage you come to a stop, pull it out of 4 high and reverse a few feet to take the load off the cams and release the hubs.

The t-case is chain driven which means there is a direct connection between the front and rear axles with next to no ability to adjust for different axle speeds, thus on hard packed surfaces the wheels are not allowed to change speed, like when turning, and this binds up the driveline. In most cases on a first gen this usually breaks the hubs first (by design), but damage can include in order of durability: u-joints, axle shafts, and even the differentials and t-case in extreme circumstances. However, mechanically speaking the 1354 is fairly robust transfer case and as long as your aren't doing anything crazy with it (37's and lockers, for instance) it will probably be the only thing that doesn't break on a first gen. Worst issue is the poor transfer case shift motor design on the electric versions.

 

[92exp4x4]

The 1354 definitely has the electro clutch assembly. Here are some pictures from the service manual. I believe the 1356 from the full size trucks was the same design, just larger.

The manual 1354/1356 t-case is mechanical, and I'm not sure if it's shift on the fly or not. The manual shift F250 I used to have was not shift on the fly. With syncros, it could have been. That would have been sweet.

Is the 4405 the later AWD case? I'm not sure which vehicles those are out of.

 

[Mbrooks420]

The 1354 is a mechanical shift on the fly t case. Many of them are manual shift, which you wouldn’t make sense with an electromagnetic clutch unit.

The 4405 is electromagnetic and that’s exactly how the automatic 4wd is possible (it’s not really AWD)

 

[92exp4x4]

The 1354 is a mechanical shift on the fly t case. Many of them are manual shift, which you wouldn’t make sense with an electromagnetic clutch unit.

The 4405 is electromagnetic and that’s exactly how the automatic 4wd is possible (it’s not really AWD)

So the 4405 is the one that is torque biasing front to rear through pulse width modulation. That must be the case some of the 2nd gens and maybe later models had. Im not near as familiar with the newer vehicles as I've not owned any of them.

But the 1354 definitely has the clutch. Its what spins up the front driveline as the motor actuates the mechanical coupling in the case to lock the front and rear drivelines together There still may be syncros involved for smooth engagement, but the clutch is most certainly there. The front axle does not turn with the speed of the vehicle in 2wd and needs to be brought up to the speed of the vehicle before t-case lockup.

 

[Mbrooks420]

I wonder what activates the clutch on a manual shift. I was under the impression there was no electronics involved with a 1354 manual.

 

[92exp4x4]

The clutch is not in the manual shift as it's designed to be shifted while stopped with the assuption that the hubs are unlocked at the same time. This allows the front axle to not spin at speed and improves fuel economy as it's not contributing to parasitic driveline drag. With the hubs locked, the axle spins at vehicle speed allowing you to shift (lock up) 4wd hi at any time.

The touch drive system was something Ford came up with to allow for shift on the fly operation of the mechanical case they already had. It's an electronic system on top of the mechanical operation of the case, if you know what I mean. It kept the driver from having to get out to lock the hubs while keeping the front drive line from turning all the time. This is also where the auto hubs come in.

You are correct in that it's mechanically locked together while in operation. You can physically rotate the actuator with pliers from underneath to do so, but if you were to do only that while at speed, the case would probably go to pieces because of the dissimilar driveline speeds. That is where the clutch comes in. It's pulsed by the module, then a second later the motor is commanded to actuate and lockup the case.

I had a full size bronco with manual case and auto hubs. It would not shift on the fly. I tried it once at low speed and it was not happy about what I wanted from it. I came to a stop and it slid right in.

 

[Mbrooks420]

Alright, that all makes sense.

 

[MrQ]

The 1356, is not like the 1354. It does have a clutch. The 1354 in both configurations does not. The front driveline does not have to be spun up since with the hubs not locked it isn't moving anyway.

The 4405 is ONLY t-case between 1st and 2nd gens that had an electromagnetic clutch. Not even the 4404 AWD T-case used one.

 

[Scorpius68]

Ok I’m not familiar with all these numbers 4404, 4405,, 1354, 1356....I guess all I need to know is mine is push button thank goodness no setting manually. My xfer case has a chain in it and don’t turn on /use 4x4 on the pavement. Once on you must be stopped to use low.
Gears I’m changing fluid this weekend just going to suction both out. Replace with Valvoline 80/90 then use good Mercon fluid for xfer case.
Now begs the question here. In the rare event it snows here in Atlanta and we have icy roads. (Not patches) I assume then I could use 4x4 mode on the roads so long there is no visible or extremely little visible road. Rare but does happen especially some back seldom used roads