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Front Axle

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LGMATT View Drop Down
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    Posted: 19 June 2021 at 1:23pm
Hi. I am new to the forum but have owned a Jeep CJ2A for a long time.  My original purchase is a 1947 but parts have been exchanged over the years.  I bought a parts Jeep that had a Buick V-6 in it.  I put what I thought were the best parts of each to make one Jeep sticking with the four banger engine.   Actually I found a 1972 Willies Industrial engine from a junk Hobart welder.  I overhauled that engine and it works just fine.  It had hardened valve seats for whatever that is worth.

The front axle on my runner is making noise on turns.  So my plan is to overhaul the front axle from the parts Jeep.  My runner still needs to do some work.   I am also considering converting to a disk brake system.

First question:  How does one get the axles unhooked?   I've determined that it is a Dana 25  model.  After the axles are out, I will continue to tear it down, clean, figure out what needs replacing and then paint  and reassemble.  Eventually it will go into my running Jeep.

One axle has the threads on the end and the other does not.  I would also appreciate information on the pros and cons of those different designs.

Lyn
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Oldpappy Quote  Post ReplyReply Direct Link To This Post Posted: 19 June 2021 at 3:42pm
The earlier axles have the threaded end, which should have a nut and washers on it. With these that is how the end play was set.

Later axles used a flanged bushing in the spindle and a snap ring for controlling the end play, eliminating the threaded end and nut.

Either will need to be set up properly with the correct bushing, snap ring, or nut.

Not sure what you mean by "get the axles unhooked", they usually come on out with a tug after you remove the spindle.

There are some Youtube videos you should watch about rebuilding the axle. Look for the videos by a guy who calls himself "Metalshaper", he knows what he is doing, and provides very good information on how to do it.


Edited by Oldpappy - 19 June 2021 at 3:44pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote LGMATT Quote  Post ReplyReply Direct Link To This Post Posted: 19 June 2021 at 4:01pm
 I have the spindles out,   Your answer, give 'em a tug is what I am looking for.   I'll go out to the shop and give 'em a tug.  I go slow so as to not mess up.  Only other axle assembly I have worked on is a Dana 44 on a Bronco II.  In that one, takes out the cross shaft in the spider, then push the axles in to the center and take out a keeper ring.  I was looking for something tricky like that.

Off to give the axles a tug.   Thanks !


Lyn
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Oldpappy Quote  Post ReplyReply Direct Link To This Post Posted: 19 June 2021 at 5:04pm
I have only pulled apart one Dana 25 and that is how those came out. Want to be careful about the joint, depending on which you have, and don't be surprised if they don't match since it seems you have one early, and one late axle.

There are 3 different types of universal joints used on the old Jeeps. If you have the Spicer joint which is like a drive shaft universal both axle shafts come out as a unit. The other two types are like CV joints and will come apart with balls dropping out, so you want to tug from the inner yolk.  
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Post Options Post Options   Thanks (0) Thanks(0)   Quote LGMATT Quote  Post ReplyReply Direct Link To This Post Posted: 19 June 2021 at 5:43pm
 Well that worked.  Axles are out.  The short axle wound not fit through the large hole in the steering knuckle support.  But that part has to come off anyway.   Next to disassemble is the ring and pinion.  Then the big clean up.

The two axles didn't come apart at the joint, but maybe the grease is holding them together.  I will have to find out what they are exactly and if they are worth keeping.

Both of these have balls and not the cross piece like a drive shaft U-joint.  That is a Spicer, you say?  The short axle has the threads on the end.  The long axle no threads on the end.

There are three kinds of joints.   Where can I read up on the good bad and ugly of each kind.   Being frugal, I will probably stick with what I have, but would be good to know the differences.




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Post Options Post Options   Thanks (0) Thanks(0)   Quote Oldpappy Quote  Post ReplyReply Direct Link To This Post Posted: 19 June 2021 at 7:27pm
Just did a search on this forum for "axle shaft types" and the first thread found has all the answers you need.

You did not say whether the axle with the threaded end still has the nut and washers. If you are going to use that axle you need to use the correct bushing in the spindle and the nut and washers / shims. Pay no attention to the BS out there that it is okay to cut off the end of the axle, as doing so removes any means to adjust the end play, and with any joint other than the Spicer type will lead to a failure of the joint.

The other side with the axle which does not have the threaded end needs to have the correct bushing made for that, which started with the CJ3A, and also needs to have the snap ring installed for the same reason mentioned above.

All of this is covered well, including pictures in the thread I found with the search feature. 




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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bruce W Quote  Post ReplyReply Direct Link To This Post Posted: 19 June 2021 at 8:28pm
  Everything you need to know about the three different types of front axle is in the Service Manual for Universal Jeep Vehicles in paragraphs M6 thru M13, pages 188 thru 193. You DO have a service manual, right?
BW 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote cpt logger Quote  Post ReplyReply Direct Link To This Post Posted: 20 June 2021 at 12:06am
Lyn, Since your question has been answered by folks who have much more experience with these axles than I do....

I would like to welcome you aboard! Welcome to the madness, Cpt Logger.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote SE Kansas 46 CJ-2A Quote  Post ReplyReply Direct Link To This Post Posted: 20 June 2021 at 11:30am
Originally posted by LGMATT LGMATT wrote:

   Next to disassemble is the ring and pinion.  Then the big clean up.




Here is where some make some mistakes. Going under the assumption that you have never done this before, I am going to make some suggestions. You don't have to follow them, but at least read what I am suggesting.

Some backgound:

All ring and pinion sets wear to some extent during regular use. Some have extreme wear, either from high mileage or lack of lubrication, or both. This use or abuse produces a pattern on the gearset that is in the case of normal wear will be what you want to reproduce when reassembling the gearset in the axle housing. If the gearset has undergone extreme wear it may not be suitable for re-installation without causing noise problems.

Okay...refer to your shop manual for procedure and torque specs...

First thing is that you want to do is make sure that you can install the differential bearing caps back into the housing in the proper position and orientation as when you took them out of the housing. If you look on the bearing cap there is a letter stamp on one side of the cap. It can be any letter of the alphabet except one that is easily confused as to whether they are upright or sideways. (example is "O" and I have never seen a "Q" used either) adjacent to the letter on the bearing cap there should be an identical stamp of the same letter with the same orientation on the housing next to where the stamp on the cap is. On the other bearing cap the same letter will be stamped on one side of the bearing cap in the opposite orientation as the other cap and a matching stamp on the housing. IF these factory stamped letters are not visible then it will be NECESSARY for you to mark the bearing caps and housing in such a manner so that the caps go back into the housing the exact way they came out of the housing. The reason for this is because during the manufacture the center pig (housing) is align bored and switching the caps for each other or altering the orientation of the caps could change the setup of the axle by a few thousandths of an inch. This isn't always the case, but it could happen.

After you have removed the differential case with the ring gear and removed the pinion gear, you can do some initial cleaning of the housing. Watch for bits of metal in the drain oil. Very tiny flecks are probably nothing to worry about, but big pieces are most certainly not a good thing.

ALWAYS replace both the pinion and differential bearing with NEW bearings and races. Doing this puts everything back in its exact place. When removing the pinion races from the housing there will be shims behind the inner pinion race. Keep these as they will be the exact ones you put back into the rebuild. Wire them together so that part of them don't get lost. When removing the inner pinion bearing from the pinion there will be a slinger on some installations, save this because it is also part of the setup that will be used to put the correct pinion depth during your rebuild. There will also be some smaller shims that will come off the pinion behind the outer pinion bearing. These are used to adjust the pinion bearing preload during the rebuild. The important thing to remember is that ALL shims go back into the rebuild exactly as they came out. With new bearings, races and the original shims and slinger (if equipped with one originally) this will put everything back exactly like it did when you tore it down. On some installation there is installed a baffle behind the outer pinion race and the housing. This doesn't effect the pinion depth but will change the preload shim pack thickness. Put the baffle back in in the same place it came from if there was one there to begin with.

On the differential carrier there are shims on each side of the carrier underneath the differential bearings. These need to go back EXACTLY like they came out. Do not make the mistake of getting them switched from one side to the other. The differential bearings should be a press fit onto the differential case. If one or both are loose, then you will need to replace the case. Make sure that the ring gear bolts holding the ring gear to the case are torqued to specs. If there are stamped keepers used to keep the ring gear bolts from backing out use them. While working on the differential, make sure that the differential spider gears, thrust washers and cross shaft are in good shape. Check the differential side gears for wear in the splines.

Now is the time to flush out the housing to make sure all the old oil and gunk is out of the housing. Pay close attention to the channels cast into the center housing that are used to force oil towards the outer pinion bearing.

Replace the axle side seals in the housing. They are there to keep the lubricant in the center housing from migrating to the outer steering knuckles and starving to ring and pinon of lubrication.

After reinstalling the pinion gear in the housing you are ready to install the pinion yoke and check the pinion preload. Make sure that the sealing surface on the yoke is not grooved or rough. If it needs replacement, now is the time to do it. Do NOT put the NEW pinion seal in place until you have the pinion preload correct. Check your shop manual for all of the proper torque specs for all of the places that will need to be torqued. (You do have a shop manual don't you?) After the pinion preload is correct the new seal can be installed and the pinion yoke torqued to proper specs.

After the pinion is back in place you are ready to install the differential case and ring gear. This may be a little difficult but usually a soft face dead blow hammer will put the case back into the housing. Try not to excessively cock the races on the differential bearing while installing the case in the housing. Install the differential bearing caps in place in the correct orientation and sides and use the correct torque on the cap bolts.

You have now put everything back in the exact place it started at.

A NEW ring and pinion installation as it left the factory will have a gear lash of .004" to .006". This will not be the case with USED gearing. The lash could be as high as .010" and still operate satisfactorily. Where some make the mistake is trying to reduce the lash by modifying the pinion depth and differential shim packs. This almost always causes the axle to be noisy because the new pattern introduced by the faulty installation causes interference during operation. The noise is caused by modifying the gearset pattern by trying to reduce the lash to a lesser amount and is almost always the best way to cause early failure of an otherwise salvageable gearset.

The idea is put a used gearset back the way it came from the factory.

Hope this helped. Good luck.

Edited by SE Kansas 46 CJ-2A - 20 June 2021 at 5:22pm
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Post Options Post Options   Thanks (1) Thanks(1)   Quote Vintage Don Quote  Post ReplyReply Direct Link To This Post Posted: 20 June 2021 at 8:11pm
That's a very comprehensive and impressively written summary, SE Kansas, nicely done - and it took some time to write, obviously. On my first Dana 25 rebuilt, I was very lucky to have JAB (in this forum) guide me through it, on a different forum. 

The only thing I might offer in addition is that there are a few YouTube videos that guide you through the process also, on this identical differential - look for videos by "Metalshaper." That helped me a lot as I did this process.

And look at it as an adventure! Expect to repeat some steps, and make a few mistakes - and ask for help and input as you go. It's certainly very 'do-able.'  And very rewarding to accomplish.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote SE Kansas 46 CJ-2A Quote  Post ReplyReply Direct Link To This Post Posted: 21 June 2021 at 9:14am
I made the assumption that the ring and pinion set is in good enough shape to reuse. If the gears are not reusable then it is a whole different scenario because the correct pinion depth has to be established to base everything else on. Sometimes by comparing headmarks on the pinion that is easy, but if the marks aren't there then it is a more involved matter.

Thank you, Don, for your gracious comment and suggestions.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote LGMATT Quote  Post ReplyReply Direct Link To This Post Posted: 21 June 2021 at 2:46pm
 Service manual would probably be very helpful.  Where can one be found?

I've made what I call and Jeep Super Book.  It is a large three ring binder with  a collection or articles and receipts and such with dates of what I have worked on and replaced.   That is a very nice write up.  Thank You.

I am pretty good at the computer cut and paste feature.   So will copy the write up into a document and save in my Super Book.  Thanks again for taking the time to do that.  Also I can take a paper copy out to the shop and use the write up as a guide at the same time.

There is a nut and washer on the shaft with the threaded end.  There is lots of thick grease in the knuckle.  So it was well lubed over the years of service.  There may be shims in the grease.  I haven't gotten that cleaned out yet.

Interesting side bit.   The original frame was broken over the rear axle and welded together again with steel side plates crudely added along the frame.   Other cut off welds etc. may indicate that this Jeep had been, at some time, a tow truck.   I suspect that a lift boom may have tried to lift too much weight and the frame broke.  

When I purchased the Jeep, it had a South Dakota license plate.   Mmmm, now that I think of it, the only thing that is still in use from the original purchase is the steering column and the radiator and maybe the transmission.  Not sure if the donor tranny or original is presently in use.  Both pop out of second gear --- rarely use second gear anyway.  The Jeep is usually either pushing snow or pulling logs.
Lyn
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Post Options Post Options   Thanks (0) Thanks(0)   Quote LGMATT Quote  Post ReplyReply Direct Link To This Post Posted: 21 June 2021 at 2:50pm
 Service manual would probably be very helpful.  Where can one be found?

I've made what I call a Jeep Super Book.  It is a large three ring binder with  a collection or articles and receipts and such with dates of what I have worked on and replaced.  

Thank you for the write up.  I am pretty good at the computer cut and paste feature.   So will copy the write up into a document and save in my Super Book.  Thank you again for taking the time to do that.  Also I can take a paper copy out to the shop and use the write up as a guide at the same time.

There is a nut and washer on the shaft with the threaded end.  There is lots of thick grease in the knuckle.  So it was well lubed over the years of service.  There may be shims in the grease.  I haven't gotten that cleaned out yet.

Interesting side bit.   The original frame was broken over the rear axle and welded together again with steel side plates crudely added along the frame.   Other cut off welds etc. may indicate that this Jeep had been, at some time, a tow truck.   I suspect that a lift boom may have tried to lift too much weight and the frame broke.  

When I purchased the Jeep, it had a South Dakota license plate.   Mmmm, now that I think of it, the only thing that is still in use from the original purchase is the steering column and the radiator and maybe the transmission.  Not sure if the donor tranny or original is presently in use.  Both pop out of second gear --- rarely use second gear anyway.  The Jeep is usually either pushing snow or pulling logs.
Lyn
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Oldpappy Quote  Post ReplyReply Direct Link To This Post Posted: 21 June 2021 at 3:20pm
"There is lots of thick grease in the knuckle.  So it was well lubed over the years of service."

Thick grease in the knuckles does not equate to "well lubed", actually the opposite.

Folks fill the knuckles with various kinds of grease, instead of the proper lubricant because they don't know how, or don't go to the trouble of fixing leaks.

Thick grease will stick to the inside of the knuckle ball and the joint will be running dry in the hole in the middle.

The knuckle needs a lubricant that will flow into the joint, but still be thick enough not to leak out. The knuckle lube they used to sell for this specific purpose is no longer available, but there is a good article on this on the Novak website with a recipe for what we call "knuckle pudding". I make my pudding by mixing 140 wt gear oil with chassis lube until I get a consistency like molasses. 

Also, the guy who goes by "Metalshaper" sells a knuckle lube that is supposed to be good, but I haven't tried that.

Pay no attention to the folks who tell you to use "Corn Head Grease", many swear by it but it is not appropriate for this, particularly with the joints you have.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote LGMATT Quote  Post ReplyReply Direct Link To This Post Posted: 23 July 2021 at 12:13pm
 After some other projects, I finally got back to the axle.  Now looking at it the ring gear, it looks pretty good.

I am wondering if it needs to be replaced.  The backlash is very small and the end play of the pinion doesn't seem to be much either.

Is there some sort of spec. for this or at this point, just do it ?

A picture might help with an opinion, but I don't see how that can be done here.

Looking for some advice,   Thanks. 


Lyn
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Post Options Post Options   Thanks (0) Thanks(0)   Quote LGMATT Quote  Post ReplyReply Direct Link To This Post Posted: 03 Aug. 2021 at 10:27am
 I found a drive line shop that will take a look at it,  Two mechanics seem nice and are willing to take a look at it.  Now the issue is to load the axle on a trailer and haul it down to their shop.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote SE Kansas 46 CJ-2A Quote  Post ReplyReply Direct Link To This Post Posted: 03 Aug. 2021 at 12:12pm
The pinion shouldn't have any end play. By "end play" we mean an in and out movement of the pinion in relationship to the housing. The pinion is always going to have a "lash". By "lash" we mean the movement of the pinion when twisting it until it contacts the ring gear from one extreme to the other extreme point of contact. Even new gears will have some lash.

However, that is not where lash is measured.

Lash is measured by a dial indicator installed on the housing and the tip of the indicator is touching the teeth of the ring gear. Rocking the ring gear back and forth without moving the pinion gear will give you a reading on the dial indicator. Acceptable total lash on a used set of gears will be in the range of .006" to perhaps .010". A new set of gears will be somewhere in the range of .003" to .005". Lash on gears that have been disassembled for one reason or another should have the lash measured in several places on the ring gear to insure that the ring gear was installed properly on the differential case. The reading on all the measurement points should be close to each other; within .001" ideally.

When disassembling a ring and pinion setup ALL shims need to be wired together so none will get lost. On an overhaul, ALL new cones and cups (perhaps some refer to them as bearings and races) need to be installed. All of the shims collected during disassembly need to go back EXACTLY as they came out of the original setup. It is NOT possible to "tighten" up the lash on a used gearset by taking shims out or adding shims to one side of the differential case. This will cause noise in the operation of the axle under street or trail conditions. The object of putting shims back in a build EXACTLY as they came out is to duplicate the SAME gear pattern relationship of the ring and pinion like it was before it was torn down.

Now, you are going to have people tell you that you can "tighten up" the gear lash on used gearing, but this very seldom works. Get a shop manual and follow the instructions. Shop manuals don't tell you to "tighten up" a lash; rather, they tell you to duplicate the pattern that has been worn into the gearset. Failure to duplicate that wear pattern will more than likely cause noise or fatal wear to the gear setup.

Most mechanics do not know as much about ring and pinion setups as they let on. I have seen many setups brought to my shop that were totally wrong and howled like a banshee in operation. Sometimes the setup was correctable and other times the setup put in by an inexperienced mechanic managed to ruin the gears. If your two mechanics work in a shop that does ring and pinion work on a regular basis, you are probably okay. If the shop has mechanics that don't do ring and pinion work at all or seldom then I would question their competence for ring and pinion work. They might be otherwise great mechanics for other types of mechanical work. Ring and pinion set up is a whole 'nother skill.

Good luck.

Edited by SE Kansas 46 CJ-2A - 03 Aug. 2021 at 3:39pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bruce W Quote  Post ReplyReply Direct Link To This Post Posted: 03 Aug. 2021 at 12:19pm
ALL of what Kansas said, X2. BW
It is NOT a Jeep Willys! It is a Willys jeep.

Happy Trails! Good-bye, Good Luck, and May the Good Lord Take a Likin' to You!

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