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TH400 article

Discussion in 'The Hokey Ass Message Board' started by Abomination, Dec 14, 2007.

  1. Those two terminals are for two different things, the top one is for the converter, the other is for passing gear, there is no ground, the case is the ground. 12 volts to the top one raises the stall.

    So I take it you've been manually downshifting, since you have no wires hooked up?
     
  2. Creature13
    Joined: May 13, 2006
    Posts: 354

    Creature13
    Member

    The th400 was attached to my Cad 472 when I got it last year. I put it in a 1930 Durant. I haven't driven it yet. I am almost ready to wire the car. I just want to wire this right. I'd like to avoid using the automatic method by using switches. It sounds like I will just need the 1 switch for raising the stall. I guess a passing gear switch wouldn't hurt also, I don't think it's necessary though since I can downshift just as easily.



     
  3. Shifty Shifterton
    Joined: Oct 1, 2006
    Posts: 4,964

    Shifty Shifterton
    Member

    Are you sure that's the ultra-rare variable converter th400 and you're not looking at your kickdown connection on a standard th400? Far as I know a 472 cad would've had the standard th400. The variable models have got to represent like 1 out of every 10,000 th400s made and you are a lucky guy to have stumbled across one. I don't know what the real numbers are, but there's a TON of standard th400s out there. Good luck with the project
     
  4. squirrel
    Joined: Sep 23, 2004
    Posts: 48,250

    squirrel
    Member

    yeah, Switch Pitch was made thru 67, 472 came along in 68, although it's possible someone could have put one behind that engine, or converted the trans.

    I didn't notice if someone mentioned yet...there were a lot of early 70s TH400s that have two electrical contacts, one is for TCS, transmission controlled spark. that's an early smog thing that electrically allows vacuum advance to work depending on if it's in high gear, under certain temperature conditions. So just because a TH400 has two contacts does not mean it's a switch pitch. Pull the pan or look at the input shaft (stator support) to be sure.
     
  5. Creature13
    Joined: May 13, 2006
    Posts: 354

    Creature13
    Member

    ok. its a '71 472. I'll check the pan. the pins on the plug are:
    top - horizontal
    bottom - vert to right
     
    Last edited: Aug 2, 2009
  6. hey thanks for posting this! i was just thinking of a TH400 with Gear Vendors overdrive in my 30 Model a w/331 hemi!
     
  7. Creature13
    Joined: May 13, 2006
    Posts: 354

    Creature13
    Member

    So if it's not a switch pitch model, I can leave both plugs unconnected, or should I use TCS?



     
  8. Shifty Shifterton
    Joined: Oct 1, 2006
    Posts: 4,964

    Shifty Shifterton
    Member

    ^You should use the kickdown but not the TCS. Good luck
     
  9. Creature13
    Joined: May 13, 2006
    Posts: 354

    Creature13
    Member

    OK... Anybody know which terminal is Kickdown and which one is TCS? There's a horizontal one on top, and a vertical one down to the right.
     
  10. squirrel
    Joined: Sep 23, 2004
    Posts: 48,250

    squirrel
    Member

    open up the pan, the kickdown is the one that goes to a solenoid can, bolted to the case right behind the valve body. The TCS would connect to a pressure switch. if you can't tell, take a picture and show us
     
  11. Creature13
    Joined: May 13, 2006
    Posts: 354

    Creature13
    Member

    I got up in there and the lead from the solenoid was broken right at the terminal. I re-terminated the lead and hooked it up. THANKS!
     
  12. A small fwiw I found during last winters differential swap.

    The T-400 trans in the car is out of a 68 Buick.

    I found the yoke in the spare driveshaft - changed for length reasons - wouldn't go into the trans because it was too large.

    Checking with the local driveline shop - good place, good work, good service and best of all the owner is a late Buick (455's etc.) afficionado - I find that the 68 Buick front yoke is smaller than the rest.

    A one year deal I understand.

    Even so, pay attention....
     
    Donuts & Peelouts likes this.
  13. I don't run the kickdown switch in my 462" BBB powered 32 roadster.

    Thinking was/is I didn't want Sweetie stomping on the throttle and having the car go sideways on her.

    She does ok, but all that torque is a little out of her realm of experience although, one day at the muffler shop, in front of the gang, she launched hard with the car not pointed straight down the road.
    An interesting ride it was and the gang enjoyed it mightily.

    ~~~~~~~~~~~~~~~~~~~~~~~~

    What will work for me on the 31 on 32 frame roadster will be setting up a kickdown switch on the B&M comp style shifter.
    If she drives that car - and she probably will - the shifer mounted switch will be a "have your cake and eat it too" kinda deal.

    Speaking for myself I like not having the switch connected at the throttle because in traffic with such a light car and torquey engine rolling the throttle on at 30 - 35 mph it scoots out of the way pretty quick without a lot of noise and burning rubber.

    So far, the cops in town like me and I like it that way....
     
  14. squirrel
    Joined: Sep 23, 2004
    Posts: 48,250

    squirrel
    Member

    kickdown is great, you should give it a try. You could put a power switch on the dash to disable it.

    The small yoke on some mid 60s 400s was not a one year thing, it was used on 1967 models also, probably more.
     
  15. Abomination
    Joined: Oct 5, 2006
    Posts: 6,701

    Abomination
    Member

    Re-read this today for the first time in a while. BTTT - this could help a few folks.

    ~Jason
     
  16. whakycus
    Joined: Jun 17, 2010
    Posts: 1

    whakycus
    Member
    from portland

    is an adapter avail. to install a cadillac th400 on a gmc small block v8. if not what are the possible alternatives
     
  17. squirrel
    Joined: Sep 23, 2004
    Posts: 48,250

    squirrel
    Member

    Hi, welcome to the hamb....what exactly is the "gmc small block v8" you're talking about? is it a Chevy engine like a 350, or some other GM engine? (buick, olds, pontiac each had their own version of a 350 for example, but GMC trucks used Chevy V8s starting in the 60s).

    THere are adapters to use the later Cadillac transmissions on Chevy engines. Look for a BOP to Chevy adapter (buick-olds-pontiac used the same bellhousing as the Cadillacs)
     
  18. guys....... this is a fantastic thread, thanks. i run a thm 200 auto overdrive trans, from, i think a 80,s firebird. good tranny, . it is behind a 229 chev v6 from a 1980 malibu 2 bbl carb. thanks again for this info. dermott.:confused::confused:
     
  19. boomosby
    Joined: Dec 20, 2009
    Posts: 413

    boomosby
    Member

    man this is great information!!! who would have thought this tranny was so popularly used!!
     
  20. Abomination
    Joined: Oct 5, 2006
    Posts: 6,701

    Abomination
    Member

    Thank you, thank you. ;)

    I'm just glad folks have found it helpful. The first post has a lot of into in it, but as you scroll down, you can see where I heaped it on, basically dumping all the data I had on the subject. It's almost overwhelming!

    ~Jason

     
  21. hotrodhomework
    Joined: Aug 23, 2006
    Posts: 99

    hotrodhomework
    Member

    I had 1969 Impala with a switch pitch th400,400 small block,and 2:73 12 bolt.When I would tow with it you could really get a load moving by hitting the switch.That was a fun car.The th400 is great transmission.The one that was in that car had been in alot of other cars.The cars would be sold off to get cars with better bodys. I would keep the trans each time and put it in the next car .The case had over 400,000 miles on.It had rebuilt three times.The frist time it had 290,000 miles on it.The last time we rebuilt it we put switch pitch in the case, a Kenne-Bell unit.The th400 is one of best transmissions to have ever been built.It can be made to shift super soft for Caddy owers or very hard for racers.Just a great unit.
     
    Last edited: Mar 25, 2011
  22. What's the standard height of the oil pan?
    I am having troubles with the current pan leaking, and was thinking about getting a cast aluminum pan, but it seems that they are to high for my application (1936 Ford Truck).
    I measure mine to be close to but a little under 2 inches. And I only got like another .750 space until I hit a crossmember.
    Found some pans online, but they seem to be between 3 and 3.750 inches, which is way to thick.
    Any Ideas?

    BTW: it's out of a 1965 Olds Starfire, if that makes a difference.
     
    Last edited: Jun 12, 2011
  23. Abomination
    Joined: Oct 5, 2006
    Posts: 6,701

    Abomination
    Member

  24. alpo
    Joined: May 7, 2011
    Posts: 692

    alpo
    ALLIANCE MEMBER
    1. 34 Fords
    2. Mississippi Hambers

    Is there suppose to be another connection for the "kickdown"?? All I have going to my 400 is a vacuum line to the modulator. That's probably why I can't get it to downshift when I floor it.
     
  25. squirrel
    Joined: Sep 23, 2004
    Posts: 48,250

    squirrel
    Member

    There is an electrical connector on the drivers side of the transmission. Wire it to a switch that closes when the throttle is open all the way, connect the other side of the switch to power (fused switched power such as an accessory circuit).
     

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  26. alpo
    Joined: May 7, 2011
    Posts: 692

    alpo
    ALLIANCE MEMBER
    1. 34 Fords
    2. Mississippi Hambers

    thanks for the info. I was wondering why I couldn't get it to go into "passing gear". Will have to rig something up for the Edelbrock Thunder carb.
     
  27. senior fried
    Joined: Jul 17, 2007
    Posts: 1,032

    senior fried
    Member

    Thanks for bringing back up !
     
  28. EnragedHawk
    Joined: Jun 17, 2009
    Posts: 1,082

    EnragedHawk
    Member
    from Waco, TX

    This is a good read. I've got a TH400 sitting in my garage that I screwed up a while back; I may have to look into rebuilding it.
     
  29. good info on older thread! does anyone know if the 400 turbo that jaguar used had its own case like AMC did?
     

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