3 speed trans rebuild

Discussion in '1947-1954' started by durangoroadboss, Feb 4, 2012.

  1. durangoroadboss

    durangoroadboss Member

    Joined:
    Apr 6, 2008
    Messages:
    47
    Location:
    Durango Colorado
    Hi folks - I'm looking to rebuild my 1952 3-speed transmission. Has anyone done this - is it reasonably doable? Where do I get parts like new second and third gear syncros and seals? I have the factory manuals, but no factory trans tools.

    In the alternative, any ideas on who might be able to rebuild this trans for me? It is difficult to shift into second gear and if you coast to a stop while still in third gear, it is virtually impossible to get the trans out of third into neutral. Thanks.

    Richard
     
  2. Blueflame236

    Blueflame236 Member

    Joined:
    Mar 29, 2008
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    Location:
    Norway
    Saginaw 3 speed rebuild !

    Hello Richard

    If posseble lift the truck with a hydraulic lift or use a old fashion carpit and support the rear part . You have to jack it up a bit. Then loosen the rear brake wires and rear end drive line to. loosen the aluminum collar and U joint. Move the whole lot backwords. Take the tranny out .

    Overhauling the 3 speed tranny is easy to do your self . You need some mechanicall insite and experience and a snapring tool wich you can buy at your locall NAPA store. Taking photos/video will help much.

    Put your cloves on. Drain the old oil out. Start cleaning the tranny outside and inside with fresh diesel or petroleum in a parts cleaner or a plastic tub.
    ( dont use high pressure neither water ). Important to have your own logicall system when taking it apart and when resambling it again. Make a close inspection of every gear , syncros and shaft when taking it apart and change out what is shipped , damaged or has much wear. Remember to check out the tranny cover parts for wear to ( forks , seals , spring ect. ) You can buy the overhaul repair kit and parts on EBAY or Patricks in Casa Grande and other truck vendors will have different parts to like Joe ( Deadzonetruckin) at this forum. The complete kit contains main bearings , snaprings, syncros , seals , gaskets ect. Use some good permatex when placing your gaskets (heat resistant type) and use some white lithium grease on the new syncros and forks (sharp edge). Then fill the tranny up with 80/90 SAE oil and your ready to test how your gears are working in the bench. Testing the gears could be simply done by using a drill and a connection to a stiff plastic tube connected to the main shaft. Rotate the tranny shaft clockwise and listen carefully if any noice or wining appears ! Use new bolts/nuts/washers when installing the tranny back again in the clutchhouse.

    There are some good instruction videos to watch on YOU TUBE (rebuild saginaw 3/4 speed).

    If you give me a pm with your e.mail adres i will send you the overhaul manual as a pdf file.

    I forgot to say that before installing the tranny back in position again you have to check up the clutch . Means the throw out bearing, pilot bushing and fork if they are in a good condition . Just look at the inside of your clutch an you`ll notice.
    Check up the all the linkage system between the tranny and the main rod thats leads to your colum lever. If it is`nt properly adjusted it gets easely stucked and wont shift aswell as it should.


    Good luck Martinius.




     
    Last edited: Feb 5, 2012
  3. vwnate1

    vwnate1 Member

    Joined:
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    AMERICA !
    Saginaw Service

    Richard ;

    That poor shifting & sticks in third gear issue means almost certainly the clutch is Foo-Bar so address that first ~ if you look at my recent (last fall) '76 GMC clutch repair posts , you'll get a comprehensive primer including the few special tools you'll need .

    DO NOT skip replacing the pilot bearing ! that's one special tool that's cheap , order it first and USE THE GUIDE PINS .

    DO NOT grind the flywheel unless it's warped or has big gouges in it from clutch rivets . just clean it hospital clean & wipe with alcohol the day you re assemble the clutch .

    The tranny's schynchro hubs , snap rings , bearings , shims & bushings etc. , are all available on Flea-Bay or @ Chevs Of The 40s " in Wa. state ~ they'll have everything brandy new , not cheap .

    Take your time and work over some big , light colored beach towels you buy at the thrift store , tranny works is simple and fun , if you don't get wound up when your re assembling the primary input shaft and have all the roller bearings fall into the sump... :rolleyes: .

    Use grease to hold the needle bearings in place and no , it is NOT O.K. to ignore a needle size space in the bearing when you're re - assembling ! .

    DO NOT trust Federal Mogul to have put the correct needles in the bag , MATCH UP everything and be sure to check each gear for tiny hair line cracks , I wipe 'em dry then hold on a coat hanger & pass a Plumber's Propane Torch over the gear , if any grease or oil oozes out , that's a crack and the gear is junk .

    Plenty of good used gears around , flip over the 1st. / Reverse slider 180° & re use it , GM designed it thataway .

    Be sure to save all the thin flat shims at one end of the cluster gear , they're REALLY important , which end of the cluster gear they fit on , is critical too , use new shims and IIRC (check the book , don't trust my memory here) you can shim the cluster gear to less than .020" for best mesh & silent operation .

    There is NO SEAL on the input shaft ! . don't panic .

    Take lots of pix , go to Chevrolet Obsolete in Georgia and download all their exploded pictures , make margin notes as you go along , have fun ,YOU can do this at home ! .
     
  4. Blueflame236

    Blueflame236 Member

    Joined:
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    Location:
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    Shims !

    Cluster gear shims are in between the case and the biggest gear , in opposite site of revers idler gear.

    Martinius.
     

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