Trans swap

Discussion in ''Da Nailhead' started by Dragdoc, Aug 31, 2019.

  1. Dragdoc

    Dragdoc Well-Known Member

    I'm tired of the pokey nature of a dynaflow trans and will be stepping up to more than 2 forward speeds.

    O.D. trans would be cool, with deep first gear to get that piggy moving and lower revs at higher speeds. But I don't do much driving above 60-65. And its certainly more expensive on all accounts. Comments on 200r4 vs 4L60e are appreciated!

    The tried and true, extra-Buicky st400 with a 300 converter is also an option. In fact, I just found a fairly local guy with a converter and core trans for $200. Cheap trans to rebuild and I can probably run the converter as is (have it tested first). I know I need a starter spacer, bushing, and a flexplate. Anyone know if a particular stock flexplate works? As usual Russ Martin wants an awful lot for a one.

    I realize this may belong in “juice box” but I think this is particular to the nailhead crowd. Chime in one and all
     
    Donuts & Peelouts likes this.
  2. if you're not a freeway type of guy why not save the $$ and just go for the ST400? I am going that route and using a 300 converter. My rear gears are 3.42 so the car should be snappy out of the hole.
     
    PGSS likes this.
  3. cobravii

    cobravii Well-Known Member

    I went with a 4L60E behind my 425 in my '64. Best thing I ever did. 1600 rpm at 75 mph and way more jump off the line.
     
  4. Dragdoc

    Dragdoc Well-Known Member

    Cobra, did you have a standard 400 in that before? And I assume you kept the same rear gears
     
  5. telriv

    telriv Founders Club Member

    Larry's '64 came with a non switch-pitch 400 originally. Stock rear gears were more than likely 3.07 or 2.92 reason initial take off is better/improved. With the 3.06 1st. gear it would now be like a 3.64 or a 3.50.

    Tom T.
     
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  6. cobravii

    cobravii Well-Known Member

    My car did have a Standard TH400 in it from the factory. It was the first year of the TH400. Tom is right, my car did come with 2.92 gears but I had a third member from a '64 Riv with 3:23 gears that I installed. It seems to be a really nice combination.
     
  7. telriv

    telriv Founders Club Member

    So now the 3.23 with a 4L60 would be like a 3.81 rear gear in 1st. gear. MUCH improved "Launch" out of the hole. Now you need to worry about the possibility of NO traction if you nail it out of the hole.
     
    300sbb_overkill and PGSS like this.
  8. Dan Hach

    Dan Hach Well-Known Member

    Is there a way to run the 4L60 without a controller?
     
  9. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    Yes, just get the older 700R4 version of the 4L60.

    Now if in you meant 4L80E then I think you're gonna need one. Quadzilla use to make a non-electronic valve body for the 4L80E years ago but when I looked for it years later I couldn't find it again on the net.:(
     
  10. CameoInvicta

    CameoInvicta Well-Known Member

    I’ve got a ST400 and V6 ST300 converter in my ‘62. With 3.23 gears and a 28” tall tire I can do 70-75mph at roughly 3000rpms. Doesn’t seem to mind the RPM.

    To swap transmissions I had to get a different flex plate (I think only certain years are setup to work with the large and small diameter converters, not 100% sure though), different starter (shorter snout), install a crank bushing adapter, get a different driveshaft yoke, shorten the driveshaft, and build a different trans crossmember. Other things to consider are the shifter, and trans kickdown/switch pitch operation.

    Overall, for my purposes, it is a much better setup than the Dynaflow.
     
  11. Opa

    Opa Torque/a 8 piston figure

    Last edited: Feb 18, 2020
    300sbb_overkill likes this.
  12. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    That's different than what they use to sell, they use to sell a replacement valve body that got rid of the electronic crap that was a bolt out the factory unit, bolt in the aftermarket unit and done type of deal that would shift by itself if you didn't want to manually shift it. But good to know there is this kit to get rid of the electronic stupid crap, thanks for posting.

    Also, IIRC there wasn't a 900 HP limit on the replacement valve body. From my CRS memory they were installing them on those stupid fast single engine race boats that sometimes flip over when they turn to fast.
     
    Last edited: Feb 18, 2020
    Opa likes this.
  13. Opa

    Opa Torque/a 8 piston figure

    Now to locate a 4L80E for a normal price down here.. and lets try it out.
     
  14. cobravii

    cobravii Well-Known Member


    I tried using a 700R4 in my Electra. it does NOT fit without major modifications to the floor and firewall. To use a 700R4 you need an adapter kit which pushes the transmission 2" back into the firewall and the top of the trans is taller than the TH400. The 4L60E has a removable bell housing allowing me to use an awesome product by Russ Martin at Centerville auto repair. Other than the harness this transmission looks like it came with the car a quick glance.

    http://centervilleautorepair.com/transadaptors
     
    300sbb_overkill likes this.
  15. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    WOW, I had a 700R4 in a '64 Skylark with zero floor mods, what year is your Electra?

    Anyway, very cool you got an overdrive in your car! And thanks for the link.
     
  16. cobravii

    cobravii Well-Known Member

    My Electra is a '64 convertible. I think the big Buicks had flatter floors.
     
    300sbb_overkill likes this.

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