U-joints? Mounts?

Discussion in '94-95 5.0 - Specific' started by A_+, Jun 6, 2014.

  1. A_+

    A_+ Active Member

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    I’ve removed rear tires and rotors to rule them out so now I plan on running it again once I get a day off. Maybe axle bearings?
     
    Last edited: Jun 13, 2020
  2. A_+

    A_+ Active Member

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    Well, running with no tires and rotors I got the same vibration. It kinda sounded like it was coming from the gears but also from the rear u-joint. I’m gonna start with the joints before I get the diff rebuilt. Also, the pass side axle moved in and out when accelerating. Not too much but, just enough to notice when you look real close. Is that normal?
     
  3. evilcw311

    evilcw311 Most Evil Member! SN95 Supporter

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    How much did the axle move in and out?? 1/4”.......1/2”........... a hair???


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  4. A_+

    A_+ Active Member

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    Maybe 2 hairs. Now that I think about it, it’s probably just the gap at the end of the axle where it clips in. Diff fluid is full too. I’d hate to replace the joints if they’re in good shape but the last shop said the DS looked good so maybe the joints went bad?
     
  5. evilcw311

    evilcw311 Most Evil Member! SN95 Supporter

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    While replacing the u joints, what would it cost to have the ds inspected and verified that it’s straight and true and perfectly in balance??

    Kill 2 birds one stone. That way before you spend money on the u joints you’ll know where you stand. And if by chance it’s the ds then go ahead and get a nice new aluminum one.


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  6. A_+

    A_+ Active Member

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    Meh, why not. Just to be safe, I’ve been looking around the Dallas area for a place to rebuild my diff and wow, prices go from $400-$1000?! Other places say they won’t even touch mustang gears
     
  7. dcm0123

    dcm0123 New Member

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    It looks like you making progress and narrowing it down.

    I would pull the drive shaft and move the bearings through their full travel. If you feel any roughness, you need to have them replaced and might as well have it balanced. Do not use Precision brand or other off brand joints, had problems with soft U-joint shafts in the past being damaged by the roller bearings. Rock Auto sells Spicer/Dana greasable which is a good choice.

    If they are OK and you want to investigate further, I suggest you take the cover off the differential.

    There are 2 bearings on the pinion gear which the drive shaft flange (yoke) is on. These bearings are supposed to be preloaded. They are tapered roller bearings. Preload means they intentionally apply a load so there is no end play in the bearings which will also put a slight amount of drag (preload) on the flange when you try to spin it. Clamp a pair of vice grips on the flange and try to move the flange from side to side and in and out. If you feel any play the bearings are bad.

    The ring gear is mounted on the carrier which also has two tapered roller bearings on it. They are also supposed to be preloaded. Take a large screw driver or tire iron and pry the ring gear from left to right. Any play and they are bad.

    Look at the condition of the ring and pinion gears- look for chipped teeth or other damage. Have a feeling you will find damage to the gears or the bearings.

    There is supposed to be a slight amount of play between the two gears which allow you to rotate them back and forth slightly without turning one another. You should be able to feel the slight drag caused by the bearing preload on each when you rotate them back an forth. No preload is a sign of bad bearings.

    There should be a slight amount of end play in the axles. There should be no up and down or side to side clearance. When you pull the axles, look for damage caused by the wheel bearing to the axle shaft

    Another place which can wear is in the spider gear assembly. To check this you need to remove the single bolt which holds the pinion shaft (cross pin shaft) into the carrier and pull the shaft out. Look for wear between the shaft and the 2 bearings which spin on it. Then check for wear between the 2 side gears and the carrier they fit into. The clearance between the gears and mating parts as supposed to a tight fit with a slight amount of clearance so they can rotate.

    An option if you can not find someone to rebuild yours is a used unit from a salvage yard. Take it to someone to have it checked before you put it in. Yours should come out easy since the control arms were replaced. If you decide to rebuild yours it could be very expensive which is often the case because the axle bearings run directly on the axles which damages them if you have a lot of miles.

    https://www.differentials.com/wp-co...ferential-and-Axle-Exploded-View-Diagrams.pdf

    Edited on 6/25 correcting some of the component names- last time I disassembled a differential was 30 years ago
     
    Last edited: Jun 25, 2020
  8. A_+

    A_+ Active Member

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    Awesome! Thank you!


    Well, just to follow up, I removed the dog bone and it sounds like the rattle went away. I didn’t hear anything on the ride to work this morning but we’ll see how it goes on my way home. I will say that I think I may need that bone back. I hit a few bumps on my way in and it hit pretty hard! I felt it in my soul!
     
  9. dcm0123

    dcm0123 New Member

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    Is the dog bone the weight which hangs below the front of the differential?
     
  10. A_+

    A_+ Active Member

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    Yes. I removed it but forgot to leave the bracket. I put it back on now so I hope it helps. I wanted to put it back but the bushings are shot. I don’t think anyone make them, at least LMR doesn’t carry them.
     
  11. dcm0123

    dcm0123 New Member

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    It makes sense this would help eliminate vibrations of the rear end as the drive shaft turns. If the bushings are gone allowing metal to metal contact it would make noise.

    However I do not think it would affect what you feel going over a bump. Is there a rubber bumper (#11) missing between the differential and the frame or floor board which is intended to prevent them from bottoming on each other?

    https://www.fordpartscatalog.com/v-...-5-0l-v8-gas/rear-suspension--rear-suspension

    upload_2020-7-10_22-51-2.png
     
    Last edited: Jul 10, 2020
  12. A_+

    A_+ Active Member

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    That’s what I was thinking too! Yes, the pinion snubber/ bump stop is there and it feels pretty solid. Maybe I should replace it anyway
     
  13. dcm0123

    dcm0123 New Member

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    Check you shocks first- are they leaking oil? Are the rubber mounts on the shocks OK and are the mounts tight?
    Is the differential hitting anything such as the tailpipes or is the tailpipe hitting the body or gas tank?
    Make sure where the control arms mount to the body they are tight and there is no damage.
     
  14. A_+

    A_+ Active Member

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    It doesn’t look like anything is hitting. I’ve never experienced anything like this until I removed the dog bone. ALL front and rear suspension has been replaced but I’ll give it another look in the morning. This Texas heat is a SOB!