Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

T400 question

Discussion in 'The Garage' started by crazyrc, Oct 9, 2005.

  1. crazyrc

    crazyrc 1/2 ton status

    Joined:
    Jan 20, 2003
    Posts:
    106
    Likes Received:
    0
    Location:
    Northern Alberta, Canada
    Can anyone tell me if I need a vacuum modulator on my new T400. I bought a TCI T400 and the general instructions state that you need to make sure to install a modulator if your tranny needs one. I know my old T400 had one in it.

    Should I re-install it on this one. This is a fully race prepped reverse manual valve body transmission. Its installed and I'd like to go wheelin, but I don't want to bugger up my new tranny.

    I can't get a hold of TCI until tommorow.
     
  2. 85burbanator

    85burbanator 1/2 ton status

    Joined:
    Feb 10, 2003
    Posts:
    577
    Likes Received:
    0
    Location:
    lake orion, mi
    is the old one bad? im not real keen on transmissions so i doubt id be of any help. any who the reason i posted is that i the valve body is the same way in the 400 i took out of my k5. the po did it and i cant stand it. what is the purpose for setting up a valve body that way?
     
  3. 1979jimmy350

    1979jimmy350 1/2 ton status

    Joined:
    Mar 24, 2004
    Posts:
    3,069
    Likes Received:
    0
    Location:
    Ann Arbor Mi
    You should always install a new modulator on a new trans mission. The only thing i don't know is wheater or not you need one with a full manual valve body
     
  4. crazyrc

    crazyrc 1/2 ton status

    Joined:
    Jan 20, 2003
    Posts:
    106
    Likes Received:
    0
    Location:
    Northern Alberta, Canada
    Thats what I'm not sure of. Its possible that I don't need it at all. Can anyone tell me what effect it has on the shifting.
     
  5. 1979jimmy350

    1979jimmy350 1/2 ton status

    Joined:
    Mar 24, 2004
    Posts:
    3,069
    Likes Received:
    0
    Location:
    Ann Arbor Mi
    It tells the Transmission the load condition of the engine it works with the govenor to determine when to shift for example if you floor it the modulator will get almost no vacum and will hold the shift out longer if you are just driving normal it will get more vacume and will shift sooner. You can try it with out it hooked up and if you can not get out of first gear you will know that you will need it. It will not hurt to just see if it will shift being careful.
     
  6. crazyrc

    crazyrc 1/2 ton status

    Joined:
    Jan 20, 2003
    Posts:
    106
    Likes Received:
    0
    Location:
    Northern Alberta, Canada
    Thanks.
     
  7. K5er4Life

    K5er4Life 1/2 ton status

    Joined:
    Oct 16, 2002
    Posts:
    1,456
    Likes Received:
    0
    Location:
    Bellflower, Ca
    You dont need the vaccum mod with a full manual valve body. When I installed my manual valve body it came with a plug that went in the bore where the modulator goes. When they put those valves in they put in a heavy spring in the pump that already bumps the line pressure up to max. Just put the mod in there (if you dont have that plug) and cap the mod with some vaccum caps.
     
  8. K5er4Life

    K5er4Life 1/2 ton status

    Joined:
    Oct 16, 2002
    Posts:
    1,456
    Likes Received:
    0
    Location:
    Bellflower, Ca
    Oh and by the way they usually take the governor out when the manual valve body goes in. :waytogo:
     
  9. Inu-Hanyou1776

    Inu-Hanyou1776 1/2 ton status

    Joined:
    Oct 1, 2005
    Posts:
    1,345
    Likes Received:
    0
    Location:
    Murphy, NC
    This was rather informative, I haven't read that far in my TH400 book yet.
     

Share This Page