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Technical Help with flathead driveline diagnosis

Discussion in 'Traditional Hot Rods' started by J. Fitzhugh, Jan 29, 2012.

  1. J. Fitzhugh
    Joined: Nov 7, 2004
    Posts: 296

    J. Fitzhugh
    Member

    At the Jalopyrama in October, I noticed after driving my '32 around the lot and up and over the curb onto the grass that it developed a reasonably loud thump - thump - thump right under my feet. Great. Back on a rollback to get home. I pulled the car off the transport and drove it into the garage and covered it up. We all know that feeling of disgust.

    Fast forward to today in late January. It is a nice day here in the mid-Atlantic with temps up near 50. I uncovered and started the car up, just to keep everything moving. Obviously, the thump-thump-thump was still there. Today, I had time to see when it occurred and when it stopped.

    Engine running - No noises.
    Moving foward or in reverse with the clutch out, thump-thump-thump
    Rolling down a hill with the clutch IN and in first gear (trans gears turning), thump-thump-thump
    Rolling down a hill with the clutch IN and in neutral - No noises
    Rolling down a hill with the clutch OUT in neutral - No noises

    My thoughts are that I have broken the 39 trans. Could it be the clutch or throw-out bearing?

    I had noticed on my drive back from York in June (about an hour's drive) that it was getting difficult to get the trans to shift back into first (at a full stop) after it was obviously heated up from driving. I had even checked the trans fluid to be sure that it had not leaked, but it was full.

    Any early Ford trans wizards have any ideas what went wrong? It was rebuilt literally 1,600 miles ago. Since I get the noise in both forward and reverse, does this automatically mean I busted the cluster gear?

    Any help would be appreciated.

    Jay
     

    Attached Files:

  2. 64gal
    Joined: Jan 18, 2007
    Posts: 147

    64gal
    Member

    Not an early trans wizard, but it does sound like a chipped or broken tooth. If that is a toploader, can't you pull the top and have a look? Good luck, Tom.
     
  3. J. Fitzhugh
    Joined: Nov 7, 2004
    Posts: 296

    J. Fitzhugh
    Member

    64gal,

    I wish it was that easy. When the interior was done last year, all the front carpet was glued to the wooden floor boards. I need to remove the carpet (likely destroy and replace the carpet) to get the floorboard up.

    Thanks
     
  4. ronnieroadster
    Joined: Sep 9, 2004
    Posts: 963

    ronnieroadster
    Member

    Jay
    It certainly sounds like an issue with one of the trans gears. Theres two things I would do first would be to remove the top cover of the trans its a pretty simple job once the floor covering and center floor trans cover has been removed. With the gear box open a damaged gear would be visible. Next remove the bottom drain plug from the gear box the gear lube being drained may contain some broken gear teeth or something else. The removal of the gear lube would help the viewing of the main cluster which would be partially covered in oil if its not drained.
    Ronnieroadster
     

  5. F&J
    Joined: Apr 5, 2007
    Posts: 13,221

    F&J
    Member

    Did you drive it in 2nd or high today? If yos and if no noise, then that would narrow it down to first rev slider or idler
     
  6. J. Fitzhugh
    Joined: Nov 7, 2004
    Posts: 296

    J. Fitzhugh
    Member

    F&J,

    It was so loud in 1st, that I really never got up to speed. Very good point. I will get it up to the top of the driveway and let it coast down in second and see if the sound remains.

    Jay
     
  7. F&J
    Joined: Apr 5, 2007
    Posts: 13,221

    F&J
    Member

    Don't know what rear end ratio you have, but can you ride the clutch a bit to get it to start off in 2nd?

    Then if it's quiet, you will know if it is a broken gear tooth, and better yet, which one.
     
  8. kevin mac
    Joined: Feb 21, 2007
    Posts: 106

    kevin mac
    Member
    from toledo,oh

    obviously you have a chipped gear problem...maybe metal into the berings... now knowing this would continued operation be adviseable? NO> think you should remove tranny asap to get fixed...you will then see what is amiss. you gotta take it out anyway...... now this is just one honest opinion......had a couple like this ...not too bad...good luck kev.
     
  9. DD COOPMAN
    Joined: Jul 25, 2009
    Posts: 1,122

    DD COOPMAN
    Member

    Like F&J alluded to above, it sounds like (from your posted symptoms) you've likely shed a tooth from the FIRST / REVERSE slider gear. DD
     
  10. F&J
    Joined: Apr 5, 2007
    Posts: 13,221

    F&J
    Member


    If you do this, and then now know it's a major piece of one tooth missing on most likely the first-reverse sliding gear...then how did it happen?, so it won't do it again.

    Sounds like you don't beat on it, but you said you were having trouble getting into first gear last summer? Do you mean it was grinding going in?

    If yes, that is good reason to now have a broken tooth. The first thought is that the freeplay on the clutch was too much, especially if it still could go into 2nd and 3rd, at a dead stop without grinding.

    But other things can cause grinding going into gear at a dead stop. If the clutch disc, or pressure plate surface or flywheel surface was warped, then it could grind, but it should also chatter badly in 1st or rev when trying to move.

    If you have a true bearing, not a bronze bushing, in the pilot at the rear of the engine, there is a chance it can be seizing up, which would cause grinding at a dead stop.

    In other words, if you do really have a broken tooth, try to find out exactly why.
     
  11. 1950merc
    Joined: Jun 26, 2007
    Posts: 161

    1950merc
    Member
    from Butler, PA

    What he said, but the more you spin the tranny not knowing, the more damage you could do.

     
  12. J. Fitzhugh
    Joined: Nov 7, 2004
    Posts: 296

    J. Fitzhugh
    Member

    Thanks for all the help. I certainly do not want to do any more damage.

    When I said that it was hard getting back into first, it wasn't that it was chattering. It was physically hard to get the shifted out of neutral back into first. Almost like the sychronizers were not working. Maybe it was the idler gear that has been mentioned.

    We will see. Time to get the carpet up and the floor out.

    Jay
     
  13. GregCT.
    Joined: Jun 16, 2008
    Posts: 675

    GregCT.
    Member
    from CT.

    I'm assuming that this is still a torque tube driveline. The thumping noise sounds more like a broken or loose collar on the rear of the trans to the tube or a worn out universal. Put it up in the air and do some investigating. If it is either of these, the rear can be pulled to repair.
     
  14. andyg
    Joined: Aug 10, 2007
    Posts: 560

    andyg
    Member


    diddo....
     

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