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Four U-Joints in one month!!?? WHAFUH? (long post) **FIXED**

Discussion in 'The Garage' started by mofugly13, Feb 17, 2003.

  1. mofugly13

    mofugly13 1 ton bucket of rust Premium Member

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    Since I bought my Blazer I put about 5,000 miles on it and one day the vibration starts on my to work. On my way home, POW the U-joint on my np203 yoke says "see ya" Some nice fella stopped by while I was on the side of the road and gave me a ride to Kragen which was a few blocks away. So I picked up a new joint, took off my driveshaft and went to my dads and fixed it. Everything was greasy as hell but the install went pretty smooth. The original joint was a spicer BTW. "Cool," I says, "won't have to worry about that for a while." Oh, and I also tried to put it into 4 loc and limp home just in front wheel drive. I thought my transfer case was messed up till my dad said he saw my front driveshaft spinning but not my axles. Turns out I have no ring gear in my front pumpkin; but thats another story, for another post. Well a week and a half later, I feel the vibe coming on again so I go and grab the driveshaft and the front AND rear joints are loose. /forums/images/graemlins/mad.gif So, off comes the driveshaft and in go two new joints. I am pumping them FULL of hi temp grease before install and after by the way. Week and a half later, incliding a 300 mile road trip, POW, on the freeway the front ujoint on the rear driveshaft goes again. It twisted the arm right out of the cap and the needle bearings are just a fine metal dust nad the shaft on the joint is bone dry. So a side of the freeway replacement in the middle of rush hour takes place. (I'm carrying spare joints by now /forums/images/graemlins/thumb.gif) Now I'm driving paranoid and every little bump in the road has me thinking my joint is going again. /forums/images/graemlins/eek.gif Well tonite I just got back from another 300 mile road trip and I grabbed my rear driveshaft and surprise, surprise, It's loose (as in where are the needle bearings?). And this time around, every time I got paranoid about the joint, I pulled over and pumped it full of grease. Sorry so long, but I'm gettin' to the point. Every time, except the very first time, the joint has failed it's because it went dry and the needle bearings disintegrated and then the shaft twisted its way out of the cap. And it's ALWAYS the shafts (arms?) of the joint that bolt to the yoke on the transfer case the other two in the driveshaft yoke have been still greased and rotaing smoothly with no play. So, I'm totally puzzled, why is it these that fail EVERY time? I've been using the GMB joints that Kragen supplies. They're made in Japan, but somehow I don't really think thats the problem. However, tomorrow I'm gonna go find some Spicer joints to have on hand when this happens again, and I'm sure it will. But, can anyone tell me why this is happening? Could the yoke on my transfer case be the culprit? I'm getting ready to do a part time conversion so I might swap it out then, but I gotta find one first. So, if anyone can shed some light on this whole thing I will be GREATLY appreciative. /forums/images/graemlins/ears.gif Has this happened to anyone before? I can change a joint on the rear driveshaft in about 20 minutes now, including removing and replacing the rear driveshaft and greasing the krap out of it before and after it's in the yoke /forums/images/graemlins/smirk.gif. But I can't for the life of me figger out why it fails the same way every time. Boy am I frustrated and sick of driving around waiting for my joint to fail again. /forums/images/graemlins/angryfire.gif Somebody please help!!!!
     
  2. 79Beast

    79Beast 1/2 ton status

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    Re: Four U-Joints in one month!!?? WHAFUH? (long post)

    Are you running crazy angles? Also, if your yokes or straps are deformed, it can put pressure on the cap unevenly resulting in broken needle bearings. I'm sure there is a reason and I hope you find it.
     
  3. BowtieBlazer

    BowtieBlazer 1/2 ton status

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    Re: Four U-Joints in one month!!?? WHAFUH? (long post)

    What axles lift and tire combo are you running sounds like you are runnign extreme angles or something is not centered right, to be getting that kind of wear there must be some vibs that you feel.....Jesse may need to chime in on this....at that rate of u-joints identifying and diagnosing, the problem and replacing the driveshaft with a balanced and built one all sound economical. Also this must be putting some sort of wear and tear on either the t-case or the R&P out back.... /forums/images/graemlins/frown.gif
     
  4. Ryan B.

    Ryan B. 3/4 ton status GMOTM Winner

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    Re: Four U-Joints in one month!!?? WHAFUH? (long post)

    The first time you broke a u joint if your driveshaft banged around just a little bit, it could be slightly bowed or tweeked and out of balance and now the forces acting upon it are going to continue to take out yer needle bearings in the ujoint.
    This has happened to my dad before, he got a new driveshaft made and it never happened again.

    IF your driveshaft has two u joints, one on each end, you need the two angles- the angle off the back of the t-case and the angle of the pinion to be within 2 degrees of each other.
    /forums/images/graemlins/thumb.gif
     
  5. mofugly13

    mofugly13 1 ton bucket of rust Premium Member

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    Re: Four U-Joints in one month!!?? WHAFUH? (long post)

    I'm running with stock springs and 33" BFG's. My driveline angles are all cool. But the first time it happened the front of my rear driveshaft did get banged around a bit. But the caps where the needle bearings disentigrate are the ones that strap to the transfer case yoke, the ones in the driveshaft yoke are still greased and looking good.
     
  6. mofugly13

    mofugly13 1 ton bucket of rust Premium Member

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    Re: Four U-Joints in one month!!?? WHAFUH? (long post)

    It did bang aroun on the pavement a bit the first time and the third time. If that was the case, that the yoke got a littlle tweeked, could I go to the junkyard and pick up just the slip yoke part of the driveshaft and fit it to my existing one? Or do they come as a matched set like ring & pinion gears? There's a 77 'Burb at my local junkyard with an np203, can I take the xfer case yoke off it and the slip yoke off the driveshaft and put it on mine?
     
  7. ZonkRat

    ZonkRat 1/2 ton status

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    Re: Four U-Joints in one month!!?? WHAFUH? (long post)

    Try bolting to the t-case first and move shaft up & down to see if ti is tight.Might be to tight on those two caps or possibly the yoke is spread a little and it's binding those two caps /forums/images/graemlins/confused.gif
     
  8. HarryH3

    HarryH3 1 ton status Author

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    Re: Four U-Joints in one month!!?? WHAFUH? (long post)

    After you have installed the u-joint, does it flex easily? It should be VERY easy to rotate the u-joint through its range of travel. The most common mistake made when installing them is to leave the caps pressed tightly against the end of the cross shaft. Then as the joint is working, the cap is rubbing the end of the shaft, causing it to overheat and burn out the grease. Then the joint fails in a most spectacular fashion. /forums/images/graemlins/shocked.gif

    Once the joint is installed you need to tap the joint body out towards each cap, to move the cap out against its retainer clip. Then the joint will operate freely and not overheat. /forums/images/graemlins/cool.gif
     
  9. mofugly13

    mofugly13 1 ton bucket of rust Premium Member

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    Re: Four U-Joints in one month!!?? WHAFUH? (long post)

    Thanks Harry /forums/images/graemlins/thumb.gif for the heads up on making sure theres clearance at the end of the cross shaft. I made sure the caps were seated against the clips on the yoke side of things, but your post made me realize I gotta make sure they're set against the retaining "nipples" (for lack of a better word) before tightening the straps on my xfer yoke. So this time I cleaned the gunk from the seats on the yoke and then pumped some grease in after they were installed but not clamped down yet to force the caps outboard. By filling the trunnion and the caps separately and then asembling tightly, I was "suctioning" the cap tight against the end of the yoke. So since I've gone 800 miles now on the latest set of joints, and they still have no play, I'm hoping that was the culprit. I have a chinese joint in there now but I have a spare slip yoke with a spicer already installed for if/when the chinese one lets go. Anyway, thanks again Harry. /forums/images/graemlins/usaflag.gif
     
  10. HarryH3

    HarryH3 1 ton status Author

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    Re: Four U-Joints in one month!!?? WHAFUH? (long post)

    Ah, another satisfied customer! /forums/images/graemlins/cool.gif

    Now you can use the money that you're saving on u-joints to turn orange and help Steve pay to keep all this great info available online. /forums/images/graemlins/thumb.gif
     
  11. mofugly13

    mofugly13 1 ton bucket of rust Premium Member

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    Re: Four U-Joints in one month!!?? WHAFUH? (long post)

    1200 miles and still tight!
    /forums/images/graemlins/usaflag.gif /forums/images/graemlins/usaflag.gif /forums/images/graemlins/usaflag.gif /forums/images/graemlins/usaflag.gif /forums/images/graemlins/usaflag.gif
     

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