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Technical Mystery solved with a bang - Exploded pinion bearings in rear end

Discussion in 'The Hokey Ass Message Board' started by Road Runner, Jun 29, 2020.

  1. Road Runner
    Joined: Feb 7, 2007
    Posts: 1,257

    Road Runner
    Member

    After 1-1/2 years of tracking down the rumbling noises from my 1952 Chevy pickup and replacing flywheel, clutch parts and transmission, I finally solved the mystery today...

    Both rear end pinion bearings (part# 3 and 4) disintegrated after they cried for help starting in February 2019... see photos
    Leaving the ring with missing teeth, while the pinion carved its pattern into the casting along the way.

    Sadly I was unable to diagnose the problem without the inevitable to happen.
    I posted a couple of threads along the way.

    https://www.jalopyjournal.com/forum...r-transmission-noise-only-under-load.1147799/

    https://www.jalopyjournal.com/forum...d-transmission-jumps-out-of-3rd-gear.1174941/


    Since that last post, we had the worst 24 hour snow dump in my area in decades, on Dec 26 2019.
    I was stuck for 16 days in 2 feet of snow until I could shovel my way out from the garage to the dirt road, taking 4 full days.
    The dirt road was wet mud puddles by then and I just barely got out to the paved road slipping and sliding and limiting the RPM revving to what was required to keep momentum and stay barely on the road and hold forward direction rolling the steering wheel wildly in all directions.
    My dogs were along for the ride next to me on the bench seat as usual and rather uneasy but trusting.

    Once I reached the paved road, I knew something broke really bad in the drive train - heavy clunking noises and broken metal part sounds.
    I immediately suspected the transmission broke, however it shifted smoothly in all gears and I decided to drive 20 miles to town regardless, get supplies and head back home, since under load the ride was pretty smooth if I stayed around 30 mph.

    Another thrilling muddy sliding fun-ride and I was home with my heart pounding out of my chest and adrenaline in my system for the remainder of the day.
    I couldn't believe I made it with all the noises and especially today after looking at what happened to the rear end.

    I suspected the useless gear-jumping transmission or maybe the U-joint was what broke, so I left the truck untouched until I found another hopefully working replacement transmission last week.

    Yesterday I put it in and today opened the rear end cover plate and learned what happened ... see photos.
    You can see some of the roller and ball bearing parts and the damage to the cast part holding the gears. The drive pinion is moving around loose without the bearings, needless to say.


    That rear end was professionally upgraded to a brand new set of 3.55 ring & pinion in 2001.
    I remember the shop said the rear was in bad neglected shape and they had to find a few parts from other donors to get it right. They advised to keep changing the gear lube once a year, which I did.

    I assume the bearings that now exploded must have been original and they didn't change them.
    Otherwise I can't explain why this happened. But I am no expert and maybe one of you guys can explain this.

    My other ride the 48 coupe has a 1954 original torque tube and rear gears, so now I am paranoid that I will go through this again one day.
    At least I now know the warning noises and sounds to pay attention to and make the proper diagnosis.


    Anyway, still have to fix this and as far as I can see I have at least three options:

    - Get another new 3.55 ring & pinion set and bearings and have it replaced by a pro
    - Get another new 3.55 ring & pinion set and bearings and replace it myself
    - Find a 1954 truck torque tube with 3.55 gear section in good shape

    My vote goes for the latter, as the truck only gets about 1000 miles per year these days.



    What do you think ?
    Has this happened to you ?
    What did you do and how did that work out ?


    Any advice appreciated greatly as always !
     

    Attached Files:

    Last edited: Jun 29, 2020
  2. squirrel
    Joined: Sep 23, 2004
    Posts: 46,099

    squirrel
    Member

    2 or 7 came loose. But that's just a guess.
     
  3. 56sedandelivery
    Joined: Nov 21, 2006
    Posts: 6,217

    56sedandelivery
    ALLIANCE MEMBER

    Oh yeah, same basic thing recently happened with my OT, DD, truck; the pinion gear shaft bearing cage started to come apart. That allowed the sleeve bearings to "jam up", locking the rear end, and then violently unlocking. After that was repaired, my transmission started making grinding noise in first and reverse gears (TH400 trans); the rear planetary took a beating from the rear-end locking and unlocking I guess ()too long of swapped in slip yoke???). Now I have to replace the TH400; I've got a couple of Switch Pitch ST400 transmissions to work with on a heavy truck. Your damage is far worse however, and being a torque-tube setup just makes it more difficult. I am Butch/56sedandelivery.
     
  4. Road Runner
    Joined: Feb 7, 2007
    Posts: 1,257

    Road Runner
    Member

    Yes, looking at the manual figure, I thought #7 right away.
    There are two of them, another one on the bottom, but both as tight and frozen as they probably have left the factory or maybe even the pro shop in 2001.

    I have to pull them to see if they are sheared off, but why would they be?
     
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  5. squirrel
    Joined: Sep 23, 2004
    Posts: 46,099

    squirrel
    Member

    When you pull it apart, you can see if the inner race is intact, nut still tight, etc.
     
  6. Cosmo49
    Joined: Jan 15, 2007
    Posts: 1,148

    Cosmo49
    Member

    Exact same thing happened to me 22 years ago on the way to work only I did not have the great adventure you had. I was sick when I pulled that rear cover off but mentally I was planning past this torque tube phase of my trucks life. Jack Halton, former Inliner's president was a mentor and he advised me to clean the axle out thoroughly and place a 3.90 third member in my 1949 axle housing and retain the axles. Torched off the pivot joints and replaced with axle saddles., maintain proper angles. To this day I have approximately 117 k miles on that 3.90 rear, Huck brakes, 1956 235 . Initially I had a Muncie 319 (3sp+od) that I bought from Jack, I now have a '69 Saginaw Borg-Warner 3sp+od.' .7 X 3.90 = 2.73, 3rd overdrive, happy cruising at 70-75 mph.
     
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  7. Road Runner
    Joined: Feb 7, 2007
    Posts: 1,257

    Road Runner
    Member

    Makes sense - now that you mention it ...
     
  8. Careful disassembly is probably one of the most overlooked parts of mechanics.


    Sent from my iPhone using H.A.M.B.
     
    Cosmo49, G-son and Road Runner like this.
  9. Road Runner
    Joined: Feb 7, 2007
    Posts: 1,257

    Road Runner
    Member

    Wow ... on your way to work 22 years ago ... that's cool to me.

    My reaction to this failure is relief right now.
    No more guessing.
    Now I have a narrower way forward in my undeterred mind.

    I have learned in the past 25 years that with anything that needs fixing and what I can learn from it, I treasure my simple rides even more and admire how they were made and designed at the time.
    I just like to preserve what inspires me and get it in working order.

    I take it from there and make sure it lasts, as good as I can learn how to.
     
    Cosmo49 likes this.
  10. Cosmo49
    Joined: Jan 15, 2007
    Posts: 1,148

    Cosmo49
    Member

    Wow, this has been my path.
    I rebuilt my Muncie 319 and had to take it apart 2 more times (insert 'Third time's a charm') because I had the od blocker ring in reversed. Frustrating? Yes, but when a self taught wanna be mechanic hits 3rd gear overdrive... I still can feel that frozen smile.

    Congratulations and good luck with your decisons.
     
  11. Budget36
    Joined: Nov 29, 2014
    Posts: 3,459

    Budget36
    Member

    Maybe it's time to go with an open rear and transmission. More modern alternatives are available.
     
    Hnstray likes this.
  12. Joe H
    Joined: Feb 10, 2008
    Posts: 901

    Joe H
    Member

    Just go to show how tough the rear end is, it made 40+ miles with no bearings!
     
    Road Runner likes this.
  13. Sorry 'bout that - but at least the rear end will good now ! Use to blow my spider gears in half all the time in my 64 ......396 4sp....in the 70's.....lucky the parts were still plentiful and cheap. 1964 SS front.jpg
     
  14. Road Runner
    Joined: Feb 7, 2007
    Posts: 1,257

    Road Runner
    Member

    Exactly what I was thinking - I knew something was seriously wrong, but the shifting was perfect and as long as it was in gear, it actually drove smooth with only mild rumbling.
    Rolling in neutral was another story.
     
  15. pitman
    Joined: May 14, 2006
    Posts: 4,918

    pitman

    ^^^ and a diagnosis, from
    Dr. Forbes! :) (good call!)
     
    Last edited: Jun 30, 2020
    firstinsteele and Road Runner like this.

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