27 & 30 spline 700r4

Discussion in 'Transmission & Driveline Topics' started by 79chevymuscle, Nov 30, 2009.

  1. 79chevymuscle

    79chevymuscle Veteran Member

    Apr 5, 2009
    Detroit MI
    Is there any way to tell what spline besides takin the converter off? Im not sure what year car the trans came out of so I am not able to tell that way either. Also are all 700r4's lockups?
  2. bigdav160

    bigdav160 Veteran Member

    Jan 11, 2006
    Klein Texas
    Yes, all 700's are lock-up. Pretty much all overdrive auto transmissions will be.

    It keeps the fluid temp down when in high gear.

    I'm trying to remember when the 700's went to the bigger input shaft. I think it was '86.

    On the right rear stamp pad is the code that will tell you the year. I took this pic off another site. I hope it's not against the rules.

  3. Battmann

    Battmann Veteran Member

    Sep 12, 2007
    North Chili, NY
    i think the changeover year for the different splines is 1984. i have an '84 TA and when we rebuilt the tranny the part store sold us a 27 spline converter. when we went to start up the car it sounded like crap and wouldn't move. after a lot of troubleshooting we found out that both 27 and 30 spline were available that year and i obviously needed the other one - too bad the parts store didn't tell me there were two options when i first went there. :(
  4. Batman

    Batman Administrator Staff Member Lifetime Gold Member

    Dec 13, 1999
    Mission Viejo, CA, USA
    I was under the impression that if the tranny has a cast-in arc on the passenger's side it was a later 30 spline unit. No arc? 27 spline.
  5. 79chevymuscle

    79chevymuscle Veteran Member

    Apr 5, 2009
    Detroit MI
    I just found out my 700r4 is out of an 82 Caprice. Guess that means I got the weak 700r4:mad:
  6. ZS10

    ZS10 Moderator Staff Member Lifetime Gold Member

    Jan 18, 2003
    BC, Canada
    88-93 non E, 700r4, are common and cheap enough, (Every Astro Van had one), that its not worth fooling around with a 87 down model.

    I don't know if the cast in arc means anything, but iirc the "K" case was for h/d applications...police pkg Tahoes/Caprices, etc. I've never heard it was a 'better' either.
  7. BondoSpecial

    BondoSpecial Veteran Member Lifetime Gold Member

    Sep 20, 2004
    Southern Maryland
    not only is that the weak one but it is also the odd ball spline count I believe.

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