View Full Version : Ham's 48: Timken Rear Axle Question

03-17-2020, 04:47 PM
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:


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...

03-17-2020, 08:10 PM
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.

03-18-2020, 01:34 PM
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!

03-18-2020, 06:17 PM
Larry, try this "Permatex The Right Stuff" https://www.permatex.com/products/gasketing/the-right-stuff-gasket-makers/permatex-the-right-stuff-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.

04-23-2020, 07:41 PM
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.

04-23-2020, 07:53 PM
That turned out Sweet Larry!!!
Nice job.

04-23-2020, 08:26 PM
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.

04-24-2020, 07:42 AM
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!

04-24-2020, 09:44 AM
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?)

04-25-2020, 07:22 AM
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.

04-25-2020, 07:35 PM
Little things you find on a Quarantine Afternoon

A. When you give a truck a thorough polishing and waxing, you find out that it has only slightly less surface area than an aircraft carrier … or so it seems. The chrome strip down the middle of the hood is going to have to come off to clean all of the buffing dust out from under the joint where chrome meets hood. Long armed grandsons will come in handy here.

B. Trucks, station wagons and sedan delivery hoods always flapped in the breeze. Willys offered a kit to reduce the flap, but I’ve no idea what was in it. Butch added a snubber on each side of the hood and at the eye watering speed of 45 MPH; the hood doesn’t flap anymore!

C. I straightened out the vent line and gave the truck a couple of runs to see what happened. AT a cold start, it pushed out a bolus of oil about an inch or an inch and a half long in the tube. (My smart daughter taught me that “bolus” was a slug of liquid introduced directly into something, like: “I’ll have a bolus of Jack Daniels please”. There is some more proper medical definition I don’t want to know). But, back to the vent tube – after a 20-mile trip around the county road circuit, it had asspirated back down into the case. I consider this annoyance solved. Thanks Bob, as you said – if there was anything thrashing around in there, it would just keep on comin’. Oh by the, it’s 85W140EP oil. Heavier than you recommended, but I don’t think it will ever get hot enough to get to 140. When I drain it, I’ll go to 75W85EP.

D. And, just to show that there is always just one more tweak to make … I had an issue that after about thirty minutes of running, the horn would not blow. Something got warm – not hot- and it just didn’t give a hoot! Now, the horn has always been a bit anemic – more a comic “oogah” than a “get outta my way” blast.

I suspect everyone else already knows what I am about to tell, but I went exploring. There is a screw on the back of the horn that just looks like it had to adjust something. SO, I got my little stubby straight screwdriver and turned it a bit CCW. The horn got more anemic and then quit. Hmmm, that’s not the way to turn it sez I to me. SO I turned it back to the starting place, back to just “oogah”. Well, let’s turn it CW some more; after about a quarter turn CW, it makes a nice “MOVE DA&&IT” sound, one I haven’t heard as long as I’ve had the truck – over 50-years. I’m still learning about this truck.

I have about a dozen paint spots that Butch has agreed to touch up once we get back to the new normal, I was talking to the granddaughter who coined the phrase that the truck was going to "spend the winter in the spa for exfoliation treatments". Her reply to my comments about little paint fixes "Aw Grandpa, she's just going to get the roots touched up". I am overrun with women ... And I wouldn't have it any other way.

Stay safe folks.

04-25-2020, 08:43 PM
Pretty productive day! The rubber snubbers should put just enough tension on the hood to prevent the Willys hood dance.

Did the Timken rear end originally have a vent tube? I wonder if it had a bronze vent screwed into the case?

A six volt horn with 12 volts applied, then turn the screw in and hold on. Definitely gets others attention.

04-26-2020, 05:50 AM
I wondered why there was no activity on KWF on Saturday, everyone was busy working on their Heeps, good job Larry it looks like you got a lot accomplished on your baby!!!!

04-26-2020, 10:21 AM
Did the Timken rear end originally have a vent tube? I wonder if it had a bronze vent screwed into the case?

It screws into the left side of the casting just above the differential case. And no, bronze would be a much kinder description of the vent, just plated steel.

04-26-2020, 10:39 AM
OK, it was a traditional vent. The bronze vents are cased in brass, but allow the case to vent, but keep oil in. They are used mostly in hydraulic systems, but also on some crank cases and rearends.

04-26-2020, 12:52 PM
OK, it was a traditional vent. The bronze vents are cased in brass, but allow the case to vent, but keep oil in. They are used mostly in hydraulic systems, but also on some crank cases and rearends.

Had there been any treads left in the casting, I would have tried this one.

Now I drop the two piece driveshaft and get new boots put on the u-joints.

04-29-2020, 07:54 PM
We're getting closer to being "done". I dropped the driveshaft today and took it to the shop to get new U-joint boots put on (you need a press to get the cross pins out and the redneck bigger hammer and a brick wasn't a good idea).

Then I realized that there are three trunnion assemblies and I had two boots - Duh.

I ordered another one from Roberts and I had it shipped directly to the shop - saves me a trip.

A question .. in the attached picture, (not my dash), what is that little hole stopper upper in the lower RH corner of the dash called? I'm sure it has a formal name, but I can't find it!

04-30-2020, 04:49 AM
A close out cap is what I've called them. A real hardware store should have them, or some auto parts stores will have them by size. A quick Google search didn't come up with any, but I'll try again after while.

04-30-2020, 06:15 AM
Home Depot or Lowes has them Larry.

04-30-2020, 07:03 AM
:... A close out cap is what I've called them. "

They are one of those things that have "trade names" that we hesitate to use in polite conversation. When they are used to close a hole in a junction box in electrical work, I've heard them called "AH covers". We all know about "da**it" clips on carburetors, and a lot of other convenient names.

I was looking through a Jeep catalog one day and saw exactly what I needed, but I turned my head and now it's gone.

04-30-2020, 07:16 AM
You are looking for a "Chassis Plug"

https://www.google.com/search?hl=en&sxsrf=ALeKk02OmpIZ2E2fFbg22P4RdbmugiOqNg%3A1588248 986190&source=hp&ei=msGqXv-VCMe5tQbR4Zpg&q=chassis+plugs&oq=cha&gs_lcp=CgZwc3ktYWIQARgAMgQIIxAnMgQIIxAnMgQIIxAnMgQ IABBDMgQIABBDMgQIABBDMgQIABBDMgIIADIECAAQQzICCABQt xVYlRxgxiloAXAAeACAAYIBiAHgApIBAzAuM5gBAKABAaoBB2d 3cy13aXo&sclient=psy-ab

04-30-2020, 08:14 AM
That's it. Thank you Sir.

04-30-2020, 05:02 PM
That's it. Thank you Sir.

When we're just shootin' the breeze, it's just as easy to tag onto the last post as it is to try to start another string.

I've griped about the ball and trunnion u-joints forever. I think it was GMWillys who pointed me to a place that talked about rebuilding the PTO shaft on a CJ-2A. The PTO shaft uses the ball and trunnion joints and I found place that sells everything I will ever need to keep them going.

I took the shafts up to the shop yesterday and with the quarantine, it was a slow day. Heath ,the guy who hauled the truck up to Toledo last year was sitting at the desk, his dad (an old coot like us who has an M38A1 like he worked on in Korea in 1963) was smoking a cigarette (!!!!!) and one of the local farmers were sitting while everyone solved problems.

When I brought in the shafts, Dad got this look in his eye and started to tell us everything about them. I had found the right place again. "Yeah, they used these on the old Dodge farm trucks. You pull this back and you slip this over this collar and .....". By the time I left, he had the first end off the long shaft. He was bored too.

I told Heath "You owe me on this one. You don't have to entertain your Dad all afternoon."

From GMWillys' discovery of how to rebuild those joints, the gentleman who posted it noted that there were 28 needle bearings in the donut on each side of the cross pin. When Dad took it apart, each side of the joint was one needle short of a full pack. He also commented "That pin is really in there tight". . Yeah. I knew there was no way I would get it out without a press.

The long shaft is done; we're waiting for the boot I forgot to order to finish the short shaft. Then, just 15 bolts and we're ready to rock - again!

Of course one of those 15 is just about inacessible once you have the emergency brake rigging on the truck.

05-01-2020, 05:40 AM
Great to know the world still exists as usual. Felt like I was walking into the shop with your description. The heat hit down here this week after a beautiful springtime. Glad to hear about the progress.

05-02-2020, 07:05 AM
I cleaned up the hardware from the drive shaft flanges and I didn't really like what I found. It appears that the 12 flange bolts were probably old hardware and several of them are showing wear where the flanges have rubbed up against the threads and at least one has a kink in it. I have decided to go to new hardware, but how can something as simple as looking for a bolt become so complicated?

I sorted out the fasteners holding the driveshaft flanges together. Once I got them sorted, I had four piles of 3/8”-24 fasteners:

Qty 7 – 1“ long, Grade 5 - full thread
Qty 2 – 3/4” long, Grade 2 - full thread
Qty 1 – 7/8” long, Grade 2 - full thread
Qty 3 – 1” long, Grade 8, 1/2 - inch thread

“Hey Bubba, if it goes in the hole, just put a nut on it and run it down”.

The thirteenth fastener is from the center-top of the center bearing bracket. The parts book says that bolt should be a 3/8”-24 x 2 ¾” bolt. Someone put a shorter bolt in that place and that makes it really hard to get to. I’m all into making life easier right now, so the longer bolt goes back in this time.

The parts book says all of the rest of them should be the same – but no hint as to what “same” should be.

Are Grade 2's OK for the flanges or do I need to go up a grade to 5's?

05-02-2020, 10:53 AM
I think you should try to find Grade 8. Of course cheap bolts will work.....

05-02-2020, 11:26 AM
"Of course cheap bolts will work....." Oh yeah - guilt trip.

Grade 8's all the way.

And a full set of needles in the joints this time.

05-03-2020, 06:02 AM
Haha, everyone needs a good guilt trip!

I was warding off any future readers that may want to use the wrong grade bolt in a "Critical Fastener" location. Because of the stress the Driveshaft assembly sees, the fasteners are critical. Not only must they come to the correct clamp load, there can be no defects. A driveshaft coming out at speed is something you do not want. It is dangerous to say the least.

05-03-2020, 07:22 AM
" I was warding off any future readers that may want to use the wrong grade bolt in a "Critical Fastener" location."

I am always willing to be the example that gets used as a teaching opportunity. My favorite college English teacher would have me put a paragraph or note card on the board (exactly as I had written it, punctuation errors and all), shake her head and say "Mr. Beardsley, whatever shall we do with this?".

Then she would use me as the terrible example.

Since we are at a point to have a lesson, teach us the difference between hex tap bolts, hex bolts and hex cap screws - I never knew there were so many choices for fasteners.

05-03-2020, 07:24 AM
I’ve found that between these 2 places you can find Anything that was ever made as far as fasteners goes they have it!!



05-03-2020, 08:57 AM
the bolt Depot is my go to for sure.

I am not worthy to teach about fasteners. I am quite familiar with them but, fastener engineering is another one of those specialties. Here's a quick explanation for "the difference between hex tap bolts, hex bolts and hex cap screws".


05-04-2020, 09:00 PM
A HEX Bolt newsletter. Who knew...

05-20-2020, 10:02 AM
I needed 12 Grade 8, 1-inch, 24-thread pitch bolts to finish up the driveshaft project. So, knowing me, I ordered an extra one so when I lost one I would have enough to finish up the job. Before I crawled up under the truck and got into the job, I opened the sack and spread out my hardware.

Yep, there were 13 bolts in the sack – but only eleven of the bolts I needed. Thanks Fastenal. I did have one ¾-inch Grade 8 that I used to put things together, but I need to replace it when I go back to re-tighten things in a day or so.

"Two of these things are not like the others, two of these things just don't belong here...". Elmo

05-20-2020, 10:22 AM
Fort Wayne Clutch and Driveshaft finished up the balancing job on the two pieces of the driveshaft. When I talked to the tech he said; “That was a really interesting job”. I told him; “That’s the general description of just about everything on that truck”.

As you can see, he added some balance weights and gave me witness marks to put it back together. But, for some reason, he didn’t realize that the holes in the flanges are not symmetrical. They are on the same radius, but they are not 90-degrees apart – so one set of marks was off by 90-degrees. When I aligned the marks, the bolt holes didn’t line up, no big deal.

He straightened the rear shaft. Now when I looked at the job sheet, it was 0.036-inches out of true when he started and the final was “within 0.006-inches”. I don’t think it was that bad to start, but he was proud of the job he did. There is a little play in the center carrier bearing that may or may not be a factor in things.

It went back on fairly easily, one of the more pleasant half-hours I've spent under the truck. I have figured out where to loop the rope around the shaft to support the flailing end while I work on the other one and I didn’t even drop the shaft on my head one time. But, if I had, I wouldn’t have admitted it to my wife.

We went for a couple of rides – and the vibration is still there. It wasn’t the driveshaft. But – now I know it’s not the shaft – and I have nice new boots on the U-joints. I need to go back to the tire shop because I lost the balance weights off the right rear wheel last summer, so we’ll see if that helps. If not – it’s probably differential noise and I don’t intend to tear that thing apart. Old trucks make noises.