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Transmission jumping out of gear mystery

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  • Transmission jumping out of gear mystery

    Most of us know of the young NYC fellow with a 29' who had his engine rebuilt and then had transmission issues well the following explains what was his issue.

  • #2
    Gee seems if you have to pull the transmission etc. You might as well as just replace the housing with a new more beefed up one..


    • tbirdtbird
      tbirdtbird commented
      Editing a comment
      Mike, I think that is their intention

  • #3
    Someone else was having problems with trans jumping out of gear and it was suggested to check the tower. In Brattons catalog jumping out of gear can be caused by a weak spring or bad plungers or worn detents. They also say the bores need to allow the plungers to move freely in the bores. With the transmission in the car, I would check the tower before removing the trans, rearend, and or engine !
    IMO I would check the easy stuff first before a complete rebuild of an car :-)


    • #4
      thanks for posting as i have followed all of Seth's previous adventures on trying to fix this issue. Where did you find this latest video? i did not see it posted on his blog pages which he keeps going. . i wonder if he got it back together and road tested yet?
      i see they did not stand the engine on end (face down) when checking the runout, and wonder how that played out in the final calculation....
      3 ~ Tudor's
      Henry Ford said
      "It's all nuts and bolts"

      Mitch's Auto Service ctr


      • tbirdtbird
        tbirdtbird commented
        Editing a comment
        I haven't seen an update to his blog in ages. I attempted to help via PM several times

    • #5
      Jumping out of gear is an all too common problem.

      IMO the flywheel housing is the weakest link in the drivetrain.
      1) Unlike the bellhousing it is not bowl shaped and thus lacks intrinsic strength by design. The reinforcing ribs are inadequate.
      2) many are cracked as this one was because a) roadside timing gear changes have triggered people into jacking up the front of the motor without loosening the motor mount bolts; the upper bolt should be removed. b) Henry made the FW housing part of the suspension, thus transmitting all the force induced by bad roads, potholes, hitting curbs, etc to that housing, and stressing it. A better design would come later when suspension components were made to stand on their own and not involve the drivetrain. The exception of course is the rear axle, which in any car is arguably the beefiest part of the drivetrain.
      3) For my build, I had access to a pile of 20 FW housings and the cracks were so fine I could not see them unless I dusted them with a sandblaster. All but one of the 20 were cracked.
      4) it will be a while before I can be convinced that stitching the cracks will cause warpage. The warp was likely there already.
      5) The FW housing MUST be properly "dialed in" to the rear of the block. Tom Endy (Santa Anitas As) has a good article on this. ( along with many other fine articles). It was mentioned early on that Seth's FW housing was NOT dialed in initially. Then, when problems arose, they were able to shove some .010 shims at the top two accerator linkage bolts. Ummmm that is not dialing in. Also, the BEST way to dial in is with the engine face down in a stand, to remove the fore and aft lash of the crank, else you can have an erroneous reading. Thus I am in agreement with Mitch on this point. Dialing in can be tedious and confusing but it must be done, and done properly. My car dialed in easily, but it took many tries to get Miles' car correct. You need to be able to access (or make) shims of various thicknesses. Just the .010 shims from the suppliers often is not enough choice. Thinner shims can be cut from main bearing shims. Please do not use aluminum as found in beer cans etc

      Perhaps when the cars were fresh on the line all that was needed was .010 shims, but these cars are now 90 years old and have 90 years of wear, tear, strain, warp, stress, etc etc on them, and the FW housing is weak to start with. Ever hear of anyone complain about problems with their bell housing? No, because by design the shape is very stable. I suspect that the car was fine before the engine was yanked for overhaul because the FW housing was properly dialed in at that point.

      Many other things can trigger jumping out of gear, and the tower should also be suspect. It is often said that you should switch to a borrowed 'good' tower for testing, but I have been fooled by that, too. Not all towers are as good as the owner thinks they are.

      The forks can have wear in the square notches, the pin holding the fork to the rail can be worn/loose, the ball on the end of the shifter can be worn, the detents can be worn, the detent springs can be weak, etc etc. All the subject of another thread another day. I have overhauled towers and had new plungers on hand, only to discover with close inspection that the original plungers were quite good (better than the repops), and that the real problem was the notch in the shift rail was worn. There cannot be any wear in any of these parts. They ALL help to hold the tranny in gear. Third is especially problematic because the throw (engagement distance) of third is so small. There is very little bite of the gears. You must have full engagement, and worn parts prevent that.

      When reassembling the detent plungers and springs, I usually add a 1/4" ball bearing to the original spring to stiffen things up. I have not found the repop springs to be to my liking.

      The quality of the gears and shafts and bearings inside the box are another entire thread, but Tom Endy has it covered well.
      He is the acknowledged master:

      Wrenching on a vehicle 90 yrs old requires basic mechanical ability, but also extreme observation and suspicion that old parts may not be what they were 90 years ago. Repops must be examined closely, because 'new' does not necessarily mean better, especially with the offshore sourcing going on today. You cannot be in a hurry.
      Last edited by tbirdtbird; 06-03-2017, 10:27 AM.


      • #6
        To add to 'tbirdbird's list, factory original Ford clutch housing to block gasket was .010 thick.

        Recent modern replacements from engine gasket packages are between .020 - .030 thick, requiring several .010 brass shims behind each accelerator mounting ear.

        If Seth is still the owner of this Phaeton, Kudos to him for not giving up on his dream but rather waiting until his blood pressure came back to normal to give the project one more try. Best of luck in the future.




        • #7
          Originally posted by Mitch View Post
          thanks for posting as i have followed all of Seth's previous adventures on trying to fix this issue. Where did you find this latest video? i did not see it posted on his blog pages which he keeps going. . i wonder if he got it back together and road tested yet?
          i see they did not stand the engine on end (face down) when checking the runout, and wonder how that played out in the final calculation....

          I was notified via my youtube subscriptions. Amazing was 0.040 vs 0.005 of an inch can do... When the day comes I have to do this, I will surly double check this...


          • Mitch
            Mitch commented
            Editing a comment
            They dont have a follow up the video the engine is still on the floor...

            I hope that finally fixes it...but who can be sure???

        • #8
          Originally posted by tbirdtbird View Post
          Jumping out of gear is an all too common problem.
          When mine started that, I ordered an F150 OD transmission kit.

          I had already made the decision to do that even before buying the Model A, this just prompted me to do it now rather than later.
          Alaskan A's
          Antique Auto Mushers of Alaska
          Model A Ford Club of America
          Model A Restorers Club
          Antique Automobile Club of America
          Mullins Owners Club


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