1. Registration trouble? Please use the "Contact Us" link at the bottom right corner of the page and your issue will be resolved.
    Dismiss Notice

Attn: Tapered 2-piece D44 axle owners

Discussion in 'Early CJ5 and CJ6 Tech' started by jayhawkclint, Dec 9, 2006.

  1. Dec 9, 2006
    jayhawkclint

    jayhawkclint ΜΟΛΩΝ ΛΑΒΕ

    Oklahoma City, USA
    Joined:
    May 18, 2006
    Messages:
    2,622
    I suppose this isn't really a tech question. Moderators, if so, I apologize. Please move/edit/delete as necessary. This is posted only in the search for knowledge.

    I am interested in getting to the truth of the tapered D44 "weak link" theory. I have read quite a bit of apparently bad press over the axle. There seems to be a demand at large to replace it with a one piece unit. The legend goes something like "You'll just be driving down the highway minding your own business and the axle will come flying out landing you on your backing plate." I've heard other variations, but that one seems to be the horror story version.

    Anyway, I would like to hear your own tapered D44 breakage story. I am interested in pure facts; I really don't want to further propagate something that may possibly be a very rare occurrence. For that reason, please reply if it has happened to you while you were operating the vehicle, or if you witnessed the event unfold first hand. I would consider a link to another write-up, but only if that account also met these criteria. In other words, just seeing the aftermath doesn't count. This is important because I would like to know:

    1) Drivetrain including estimated rear wheel horsepower, gearing, tire diameter, tire type, and as many other specs as possible.
    2) What action was being taken at the time the axle broke.
    3) Did the axle come sliding out, wheel and all, or did your axle just break inside the housing and the wheel stayed mounted.

    I am particularly interested in number 3 above because I have read posts in the tech section of owners having serious difficulty getting the axles to bust loose when performing periodic maintenance. I am curious as to whether the same difficulty would be present in a carnage situation.

    Thank-you in advance for you help.
     
  2. Dec 9, 2006
    sparky

    sparky Sandgroper Staff Member Founder

    Perth, WA
    Joined:
    Sep 20, 2002
    Messages:
    9,221
    Interesting question Clint.

    You know how hard it is to get these things off when you want too... ;)

    BTW, when you tag stuff, it'd be more effective if you didn't separate every, word, with, a, comma. That way the tag would be "tapered 44 breakage". The "breakage" tag won't mean much for someone looking at the tags.
     
  3. Dec 9, 2006
    jayhawkclint

    jayhawkclint ΜΟΛΩΝ ΛΑΒΕ

    Oklahoma City, USA
    Joined:
    May 18, 2006
    Messages:
    2,622
    Roger.
     
  4. Dec 9, 2006
    Ol'Jeeps

    Ol'Jeeps Dis Member

    Lincolnton, NC
    Joined:
    Dec 6, 2006
    Messages:
    11
    Hey Clint

    What I know/have seen of Dana 44 two piece axles.

    I run them. Two others of us run em. Only guy that has broken them so far is the GPW with the old L-head!

    They can break, as can any axle. Keep in mind that these were only rated for the small tires and small HP. I drive mine on the street and trails with a welded rear diff. (I run 35 psi in 33x12.5 tires on 8" wheels on the street, to help alleviate too much stress, and try to keep the sharp turns as wide and smooth as possible!) We think the ol GPW broke his, due to Stress and old age. (his Jeep is twenty years older than ours!) He had been drivin on the street, runnin a welded Dana 41 with 33x12.50 tires at 28 PSI on 10" rims! They later broke one after the other on two successive off road trips.

    All the breakages I have seen has happened inside the axle tube. Near the carrier. (I believe this is because that is the smallest diameter on the axle length. Probably by design!) And no, the axle doesnt come out because the bearing retainer holds the bearing, and thus the axle, in the housing.
    Im sure they can be broken at the hub, and the wheel fall off, but this isnt going to be a case of twisting the axle off but rather some kind of a shock that fractures the axle. (Or frying a bearing so bad it anneals the axle righ there.) Most probably, this would happen on the trail. (Or a really serious pot hole at high speed...which would break any axle! LOL!)
    Im touching wood when I say this, but I reckon I have been lucky that with all the street driving and fairly rough trail riding, I havent broken one. Maybe cuz I carry spares! But I also have learned some finess in crawling over rocks and obstacles. (I actually too often hit them harder than I would like because of running 4.27 gears! They seem a little too high, so often I need a little momentum!). A little throttle finess also saves driveshafts, transfer cases, transmissions, etc, as well as axles!

    So if you have big tires, big hp, ya gotta go easy on em! If ya like going all the way across the rock garden with the front wheels in the air and the back wheels smokin, ya better upgrade!

    Hope this helps.
    Scott:hurrican:
     
  5. Dec 9, 2006
    jayhawkclint

    jayhawkclint ΜΟΛΩΝ ΛΑΒΕ

    Oklahoma City, USA
    Joined:
    May 18, 2006
    Messages:
    2,622
    So that was a swapped in 41? According to this chart, a 23 came stock:
    http://www.californiajeeper.com/axle.htm
    I appreciate the info, and I understand the similarities, but for semi-scientific purposes, I would like to find information specifically about breaking the 44. My theory is that the axle is built for a much higher curb weight than our JEEPs, and therefore, even with years of misuse, abuse, and possibly lack of maintenance, widespread warnings of breakage, and especially of wheels falling off, are not as warranted as what urban legend may lead us to believe.

    I share this belief, too, and that is why I am curious about the myth that you could be just driving down the highway and suddenly find yourself riding on the backing plate. I think it was in JP where I first read this, and have seen it posted on at least two tech sites, as well. Even here, possibly the most level-headed jeep site I've found on the internet, I've witnessed infrequent heresay reference toward it.

    This little tidbit I've never heard mentioned in connection with the 2-piece axle breakage theory. Thank-you very much for sharing that.

    Please post your stories! I'd love to find some concrete evidence about this theory, either to confirm or deny it. I don't run a 2-piece 44, so I don't have any vested interest, but I know there are a LOT of JEEPs on the road and trail with the 2-piece 44, and I just haven't heard any first hand accounts that would support what the theory purports.
     
  6. Dec 9, 2006
    Ol'Jeeps

    Ol'Jeeps Dis Member

    Lincolnton, NC
    Joined:
    Dec 6, 2006
    Messages:
    11
    Not sure why it would have had a 41, but the 41 uses the same axle as the 44. (10 spline, 19 came later) In fact if I understand correctly, they are the same rear except the ring gear is real thin! 44 ring gear is much meatier. (is that a word? LOL)
     
  7. Dec 9, 2006
    Patrick

    Patrick Super Moderator Staff Member

    Los Alamos, NM
    Joined:
    Sep 22, 2002
    Messages:
    8,360
    As far as I'm concerned, if the taper on the axle is clean, and the inside taper in the hub is clean, the key is in good shape, and the nut is torqued properly, they should be pretty strong. That being said, I run the two piece axles, with 1 1/2" wheel spacers, and do quite a bit of moderate 4 wheeling, and haven't had a problem. I'v busted a T86 and three T14's on the street from flat out abuse, and the axles are fine.... FWIW
     
  8. Dec 9, 2006
    mpc

    mpc Member

    Vista, CA 92083...
    Joined:
    Aug 18, 2005
    Messages:
    779
    What size tires are you running Patrick?
     
  9. Dec 9, 2006
    Patrick

    Patrick Super Moderator Staff Member

    Los Alamos, NM
    Joined:
    Sep 22, 2002
    Messages:
    8,360
    32X11.50 pro Comp MT
     
  10. Dec 10, 2006
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Tantallon, Nova...
    Joined:
    Nov 22, 2003
    Messages:
    8,102
  11. Dec 10, 2006
    TigerShark

    TigerShark Sponsor

    St. Louis, MO
    Joined:
    May 27, 2004
    Messages:
    333
    In High School I was driving my '68 CJ6 (F134, D44 w/ 4.27 gears, 10-15 tires) and came to a stop sign. When I went to pull out into traffic the Jeep wouldn't move. The engine would rev, etc. I checked different gears. It still didn't move. My friend jumped out and looked underneath and saw the rear driveshaft turning. I freaked out, being a dumb teenager, I had now idea what was wrong. I was only about 2 blocks from home, so my friend suggested that we lock the front hubs and see if it would move in 4-Wheel drive. It did, so I drove it home. Assuming I broke something in the rear end I called the local garage to have it towed to get it worked on. When the tow truck hooked up and lifted the Jeep from the back, the rear wheel just fell off as soon as the tire was in the air. Of course my mom went nuts, scolding me on how that could have happened on my short drive home.

    It turned out that I sheared the key between the two halves of the axle and the hub portion just let go.

    Obviously this wasn't a broken axle, but it was part of the axle, it was broke, and the wheel fell off :)

    Jim
     
  12. Dec 10, 2006
    Gixx

    Gixx Member

    Albuquerque, NM
    Joined:
    Mar 28, 2005
    Messages:
    111
    I have a '68 CJ5 with the V6 (all stock engine) with a lock-right locker and 33x12.5 tires. I "spun" a hub on the rear tapered axle after I had just installed the locker. I apparently did not torque the hub on properly or installed the key incorrectly. It took about a week of moderate driving and a few short off-road treks and then the hub spun on the shaft. The nut kept the hub on the axle, but the axles was spinning in the hub. This chewed up the taper and hub, so both needed to be replaced. I immediately looked into one-piece axles, thinking this was a poor design, prone to failure. I had a set of axles and replaced the "spun" hub and axle. This time paying great attention to details. I found a deal on a set of spares to carry with me and then took it to MOAB, Utah and did some fairly extreem wheeling. I am still on this same axle and have had NO PROBLEMS since, even with a Lock-right Locker in the rear axle.
    I think installation is key and they may be weaker than one-piece, but generally the scare is a bit over-hyped.
     
  13. Dec 10, 2006
    mb82

    mb82 I feel great!

    Charlottesville Va
    Joined:
    Mar 17, 2003
    Messages:
    2,706
    Ok to give an idea of the strength of the 2 piece rear axle I know a guy running one with a lockright and 35s. He plays with all the tube buggy guys so you know he doesn't baby it all the time. Rarly breaks axles. He runs a 27 up front the same way.
     
  14. Dec 10, 2006
    Ol'Jeeps

    Ol'Jeeps Dis Member

    Lincolnton, NC
    Joined:
    Dec 6, 2006
    Messages:
    11
    I have heard thats why the 2wd Low is locked out! Been tempted to remove that pin myself!

    GIXX:
    I agree, They gotta put together right and treated right. Of course wheeling with a basically stock '67 CJ, requires the whole deal kinda being "treated right" any way! LOL

    I would venture a guess that many "horror stories" about the two piece axles could be traced to a bad assembly procedure. Or abuse that would have broken 'bout anything!
    Scott:hurrican:
     
  15. Dec 10, 2006
    jayhawkclint

    jayhawkclint ΜΟΛΩΝ ΛΑΒΕ

    Oklahoma City, USA
    Joined:
    May 18, 2006
    Messages:
    2,622
    Thanks Howard. That is exactly the kind of info I am looking for. I would still like to find more accounts of the 44 in order to account for possible differences in materials and processes between the eras, but put into a whole, that info might help build a better picture of the tapered design in general.

    Gixx, to clarify, did you replace with two piece axles and have not had a problem since, or did you replace with one piece? Considering the timing of your spun hub in relation to the locker installation, how confident are you that there was no other reason than re-installation that caused failure?

    Jim, this is exactly the kind of story that I've heard relating to the "weak link" theory. I am assuming only on key broke, and only one hub fell out, yes? I am also assuming open diff since one side was enough to cause the JEEP not ot move, right? Was there any kind of maintenance done to the JEEP prior to the incident? Had you been wheeling at all? Were you, the high school teenager, the primary driver? Was there any incident that happened after this? Do you have any theories about why the wheel didn't fall off on the way home, but did as soon as the tow truck picked it up?
     
  16. Dec 10, 2006
    Posimoto

    Posimoto Hopeless JEEP Addict

    Minden, Nevada
    Joined:
    Aug 7, 2003
    Messages:
    4,538
    Here's my story, and I'm sticking to it. My first Jeep was a '54 Utility Wagon. Super Hurricane 6 cyl with a T90 and a 2 piece tapered D44. This was in the late '70s. I was running a set of True Trac tires, basically a Mud Terrain tire, 33 x 12.50. My breakage was due to youthful stupidity. Not that I don't do stupid things now. Just more mature stupid things. I was in a snow covered parking lot and was punching the gas and letting it off to see how much wheel spin I could get in 2WD and wham! All of a sudden I wasn't going anywhere. I had come across a small patch of exposed asphalt and suddenly got a whole lot of traction, at just the wrong time. I wasn't much of a mechanic then, but I looked out the door at the rear wheel and I could see it kinda moving around, but not rotating, so to speak. I engaged the front axle and drove it home. I drove on the front axle for about a month before I got the new axle shaft (made in Spain by the way) and put it in. I never considered that the whole wheel might come off. I had no idea really how any of the rear axle was held together. I had to pull the diff case to get the broken stub out. It had sheared off at the splines as where they entered the case. I still have the short piece in the garage as a reminder.
     
  17. Dec 10, 2006
    jpflat2a

    jpflat2a what's that noise?

    Hermosa, SD
    Joined:
    Jul 30, 2003
    Messages:
    8,513
    I've broken 3 of the tapered axles, 2 short side, 1 long side.
    A tapered shaft supports the vehicle weight as well as drives the wheel.

    The first was in high school, 1976.
    F4, T90, OD, D41, 5.38, 11.00 -15 Delta Floats, 15x10 wheels.
    I was showing off on the street, 4wd low range, front hubs unlocked, (which makes it 2wd low range). I would start out in 2nd gear, chirp the tires shifting into 3rd gear, then chirp the tires again shifting into 3rd over. I could beat most of the muscle car guys at school, but only in the first 40 yards of the race. Anyway, one of these "races", the left rear (long side) axle broke, just inboard of the bearing. Although I was able to drive home, the wheel wobbled so bad, I though it would fall off. The brake drum was grinding and hitting the top and bottom of the backing plate, due to the extreme wobble; it really sounded bad and watching it as I was driving home, I could tell that I really shouldn't be driving it.

    The second axle to break was a right rear axle, short side.
    By now, I had a D44 axle with powerlock in the rear.
    V6, T90, OD, D44, 5.38, 31x10.50 BFG MTs, 15x7 wheels
    This occured on a Jeep trip in 1987 ?. So Cal desert area. Leading the run, I was following an old Jeep road. The road climbed up and out of a wash, maybe a 12 foot climb. It was not difficult at all and I was in 2wd first gear, just poking along. Half way up the climb, the Jeep quit going forward; I had heard the snap just before forward momentum was lost. I had to back down and check the Jeep over; sure enough, right rear snapped. I drove it back to camp gingerly, with the wheel wobbling all the way; this one also broke out near the bearing. This failure caused a 200 mile round trip to home and back to obtain another axle and the tools and perform field repairs.

    The third axle to break was another short side, the replacement axle from the above failure. About 1992.
    V6, T90, OD, D44, 5.38, 31x10.50 BFG MTs, 15x7 wheels
    I was literally backing out of the driveway of our mountain cabin, heard the snap, and the Jeep started to roll forward while still in reverse gear. I knew what it was as I had heard that noise before; once again, investigation revealed it broke just inboard of the bearing. This repair required another lengthy trip to obtain another axle and tools to swap it out in the driveway.

    It was this last incident which caused me to switch over to a full floating set-up. At least the wheel wouldn't wobble and possibly fall off.

    The first failure was directly my fault, I was abusing the Jeep.
    The next two I don't know; I suppose I could have fractured them on a previous off road outing, and they finally chose the time and place to seperate. I'm not abusive, (read: airborne and heavy throttle) so who knows.
    The only conclusion I could draw from is that they were aftermarket, foreign made axles, as Dana/Spicer had ceased manufacture of them by this time.
    Let me say that I would avoid any D44 tapered axles today from Crown, Omix Aida, whoever, as they are all foreign made. This would exclude any made by Moser, Dutchman, etc, as I'm sure theirs are better quality.
    I would take an old beater, used, boneyard, donor D44 tapered shaft that is Spicer marked, anyday, over any of this new junk of today.

    So lets talk axle shafts.
    Want to have some fun sometime ?
    Pull your axles and draw/paint a straight line down the shaft.
    Fast forward a couple years; pull the axles again; check the lines you made previously; don't be surpirsed if the lines aren't straight anymore!
    The axles will twist due to torque and traction. I have seen marked axles go 180 to 270 degress before breaking, mostly out of sand drag Jeeps.
    It also makes sense to me (maybe nobody else) that the short side shaft will break more often than the long side. Why you say ?
    The longer shaft is more, well, longer, and can absorb more stress and flex and twist with that stress. The short shaft can't do that as well, and it breaks. In our shop, I have seen axles broken inboard, near the splines, and outboard near the bearing where all of mine occured.

    Let's talk repairs.
    Repairing a broken axle on the road or trail at anytime can be a difficult and trying experience. It doesn't do much good to have a spare axle if you don't carry the tools to swap it out: hub puller, socket and breaker bar, slide hammer, etc, you get the picture. Then you still have to fish the broken shaft out of the tube, depending on where the break occured. If running a powerlock, you have the thrust button to deal with as well.

    What to do ?
    If you're gonna carry a spare with you, either back at camp (saves 200 miles) or in the Jeep, here's what I would do.
    Grease up a bearing and install it on the shaft; place the cup over the bearing and wrap it up good in plastic. Get a used wheel hub; put wheel studs in it; get an axle key, nut, and washer as well. Don't install it on the axle! This will be your emergency repair axle and hub. Carry it with you. You won't have to deal with a hub puller and installing a bearing out in the field; if your drum is swaged to the hub, don't worry. Just pinch off the brake line and go without the drum. Don't worry about the seals at this time either; just use them as they are. These are field repairs, you have to do what you have to do to get back to home or camp, MacGyver style.

    Hub and axle failure.
    In my opinion, it's due to the nut coming loose, and/or the hub cracking thu the keyway, which causes excessive play, which leads to failure. This could also be caused by improper installation/nut torque as noted in a previous post.

    In closing, let me just preach that all 4 wheels on your Jeep are needed to get you back to camp, home, or out of a bad situation. A tripod Jeep really isn't much good. No matter what situation or catastrophic failure might be presented before you, you still need four good and rolling wheels to get you where you need to go. Take good care of them.
     
  18. Dec 10, 2006
    Patrick

    Patrick Super Moderator Staff Member

    Los Alamos, NM
    Joined:
    Sep 22, 2002
    Messages:
    8,360
    So had nothing to do with the two piece....
     
  19. Dec 10, 2006
    Posimoto

    Posimoto Hopeless JEEP Addict

    Minden, Nevada
    Joined:
    Aug 7, 2003
    Messages:
    4,538
    That reminds me of another incident. This one wasn't a total failure though. I couldn't seem to keep the axle nut tight. I kept tightening it, and it kept loosening up. This was on the Utility Wagon I mentioned above. I pulled the hub and found a crack in the keyway on the hub. Apparently on a previous install I hadn't put the key in properly and it had wedged in the slot on the axle a little too deep. Because of that the hub wasn't able to go completely onto the taper, this caused the crack to form as I repeatedly re-tightened the axle nut. The proper way to install the key is: place the hub on the axle and align the keyways. Insert the key with the taper facing toward the axle, tapered end first. Put on washer and nut and tighten. This way the washer pushes the key in as the nut tightens and you won't have the key bind up in the slot. Tighten it RFT. I think the book says 150 ft lbs. minimum.
     
  20. Dec 10, 2006
    TigerShark

    TigerShark Sponsor

    St. Louis, MO
    Joined:
    May 27, 2004
    Messages:
    333
    I can't remember 100%, but I think the key sheared or broke, but only the hub fell off. I just remember how relieved I was when the tow truck driver pointed it out and said it was an easy fix. I was the primary driver, only very light off road use. The tires were 10-15's which I think relate to about 31's by today's standards, so they were larger than stock. Open diff. No maintenance prior to the problem. I think the wheel stayed on just long enough to work the nut off the end of the shaft (about 1/2 mile). No other problems after.

    Jim
     
New Posts