Ham's 48: Timken Rear Axle Question

[LarrBeard]

For an axle that was offered as an option for a number of years, the Timken axle still is a mystery.

On the driver side of the clamshell differential, there is a vent. I suspect the vent is supposed to be spring loaded to allow pressure to vent out of the gearbox to keep from blowing oil out through the oil seals out on the end of the axles.

But - on my Timken axle vent, the spring in the vent has ceased to be a spring and it has turned the vent into an oil geyser. The truck is piddling on the floor - not a good condition.

I've found no reference to a vent for the Timken axle, original W-O part number 644089.

The vent for my axle threads into the axle housing with a tapered thread.

But, there is a vent for a Dana front differential:

https://www.kaiserwillys.com/front-d...ith-dana-25-27

This seems to be a straight thread. What are the threads for this vent, 1/8 NPT?

I may take this vent and use the spring out of it to rebuild my vent. Desperate times demand desperate measures...

[bmorgil]

Yes 1/8" pipe thread on the Dana vent. However, there is no check valve in it. It is a metal cap crimped over an open tube. It defines cheap. And they still are. For fording water, a rubber line was connected to the axle at the vent hole and run up to the body. That method is still used today.

Maybe thread a hose barb fitting in there and run a line up to the bottom of the bed.

Are you sure on the lube level in the diff? Very little over, is very turbulent inside the housing. It can cause it to piddle. One other thing, the accumulation of a lot of condensation in the lube will cause a lot of foaming in the housing. It causes many problems. One of them is oil dripping out of all orifices.

[LarrBeard]

As usual with Old Jeep Projects, what you “know” often turns out to be something you really didn’t know. I’ve griped about rear axle vents leaking oil for a bit, so today while we’re in coronavirus isolation I decided to crawl up under the truck and take a really close look at the problem.

For whatever reason I’m a bit more limber than I was a year ago, so I pretzeled myself up around things and looked at the vent very closely. As they say in football; “After further review, the initial decision is overturned”. The truck was piddling oil profusely yesterday, but there was no oil up around the vent – it’s not coming from there.

I put some solvent on a rag and I cleaned off the left side of the differential/axle joint very well. Hmmm, there seems to be a gap between the axle housing and the differential from about 5 o’clock up past 10 o’clock or so. There is even an area of bright metal showing and the paint around that area has split apart. When I looked at the passenger side – there is no gap and no leak. Something is different here.

The Timken differential case is a clamshell casting. The axle housings look like they were pressed in and secured in place by several big rivets, a two piece assembly. The axle housing has moved in the differential casting, leaving a small void that allows oil to leak out of the axle. Since it is at the bottom, gravity works well to let oil drip out.

I checked the differential lube level, and it is way down – below pointer finger reach – so I’ve lost a good bit of oil out of there. My plan is to clean up the area as well as I can; lots of degreasing spray, carburetor and brake cleaners, high pressure air and maybe even alcohol to get as much oil away from the area as I can. Then I plan to work a sealer into the crack at the seam and run a bead of sealer around the entire joint. (It’s not big enough to pound caulking into it like you would do to a seam on a wooden boat – thank goodness!)

If anyone has a better idea – feel free to share!

I wondered if having the frame straightened might have been the cause of this, but that area has been leaking and dripping for a long time. I suspect it’s just 71+ years taking its toll. Of course I wonder if the left axle housing has cracked at the rivet holes and is compromised – I guess I’d better not load a ton of gravel on the truck to make footings for patios or it might just break in two!

[bmorgil]

Larry, try this "Permatex The Right Stuff" https://www.permatex.com/products/ga...-gasket-maker/ . I have been successful sealing up leaky engines with this. Follow your cleaning process, I think this will stop it. I have used this on leaky oil pan gaskets. It isn't permanent but it lasts a while before it starts again. A cleaning and reapply and all is well again.

The frame straighten could have aggravated the issue but, it shouldn't have caused it. The rear spring pads create a lot of rotational force against the center section, and the desire for the tubes to rotate is extremely high under torque. This is why the rivets are there. Repeated torque cycles can loosen the rivets. In other words it's old age. The Dana's are puddle welded in many spots to prevent the rotation.

[LarrBeard]

OK guys, here is the interim solution to the problem with the vent on the differential. My machinist buddy turned a plug out of Delrin that had the dimensions to screw into the remains of the threads in the differential casting, a nice hex for a half-inch wrench and a through-hole tapped for a compression fitting. He even had a nice piece of nylon tubing for a vent line.

The first two pictures show the adapter installed in the casting. I tried to thread the Delrin into the remains of the threads, but no luck. He had also made me a nice brass drift tool to pound (uhh, “tap”) it into the hole if it wouldn’t thread in. SO, I took my little hammer and pounded that sucker in there – taking care not to break it off in the hole!

Then, per BMorgil’s suggestion, I made me a nice fillet of Original Formula JB Weld around the base of the Delrin plug. I let it sit for a couple of days to cure and I added the fitting and the vent tube. As you can see in the third picture, I put a curly-Q in the tube, tied it to a brake line, ran it up to a brace under the bed and zip-tied it off there as well.

Well, so far nothing of the repair leaks, but the old beast still does interesting things. After a first short drive, nothing around the axle leaked, but there was a slug of oil about 2-inches long in the tube that had been thrown out of the vent hole. It settled at the bottom of the curly-Q circle. Predictably, the next time I drove it, as the differential heated, the air expanded and, son-of-a gun, it pushed the original slug of oil out the top of the tube. It made a little mess, but nothing to what it had been doing.

I think the solution will be to just run the tube straight up to the bracket under the bed, maybe make a curl up there. That way, any oil that gets pushed out through the hole will not settle in the tube and will (hopefully) drain back down into the axle. (Surely it won’t throw enough out to fill up a 12-inch vent line)! There seems to be a lot of oil getting sprayed around in there – I find it hard to believe that the original vent could contain it.

And (a), the axle is not overfilled, just up to the joint of my pinky finger stuck in the fill hole; and (b) it has the correct weight 90W130 EP oil in it.

But she sure is running nice. I have it about 1/3 polished out after the repaint, but it will need a trip back to Butch’s for some touch-up. Once I get it polished up, we’ll have a reveal like they do on the fashion TV shows.

[TJones]

That turned out Sweet Larry!!!
Nice job.

[okiemark]

Good old JB weld. I doubt if there are many restore jobs that don't have some somewhere. I used it to seal a leak rusted in the bottom of my oil bath air cleaner. I used it to seal some holes in my gas tank but the farther I went, the more holes I found so had to cough up the cash for a new tank.

[bmorgil]

At this point Larry we are going to have to make some "Field Decisions". There is no real reason this should be happening other than lube is getting driven up into the vent where it is hanging. As the axle heats up the heat in the axle builds a little air pressure and the vent is is essence blocked by the lube that has splashed up. The air pressure builds and pushes the trapped lube out and on the floor. There is really nothing else in there that can cause this. First the tube has to go straight up. It must not exasperate the issue by forming a "trap" or a loop. Next we are going to have to experiment with the lube level. There is simply too much turbulence in there. This is probably more due to modern lube characteristics and/or a change in the position of the fill plug (which changes lube level) do to spring sag and softening, and maybe even frame changes. I don't wish to cost you but, you could try two things. A 75 weight hypoid gear oil and lower the lube level down 1/4" from the fill hole.

This is interesting to me because I had an issue in warranty that was exactly this. It was eventually fixed with all 3 remedy's. The lube level in the axle was reset (the plug hole was lowered), the lube was revised and the tube was installed and ran up to the body. The complaint was exactly the same. People drove their expensive vehicle and after a run, would find a small puddle of stinky gear lube in their very expensive garage!

[LarrBeard]

First the tube has to go straight up. lower the lube level down 1/4" from the fill hole.

A. I've already decided to reroute the tube and get the curly-Q out of the system. It seemed like a good idea at the time, but I've never had a bad idea on purpose.

B. The lube level is still "pinky level" down from the fill hole. I've got a little short pinky, but it's not at "dripping out the hole" full. (How are those for exact engineering units?)

[bmorgil]

Perfect engineering terminology, it is technically very sound. I would take it down to "Can barely touch with pinky". What gear lube weight is in there? If it is a heavy SAE 140, I think you need to try something with an SAE of 75W85. This is real good stuff. https://www.redlineoil.com/75w85-gl-5-gear-oil. I think the location of the ring gear in the housing on that Timken, puts the ring gear very close to the vent. In the old days it was probably filled with some form of Mineral oil that didn't have a lot of "clingy" modifiers in it. A heavy oil would really create some increased oil sling. I also think straightening the hose is going to help a lot. Maybe try that first.