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Transmission lines TH400

Discussion in 'The Hokey Ass Message Board' started by chopper526, Aug 24, 2012.

  1. chopper526
    Joined: Sep 12, 2010
    Posts: 252

    chopper526
    Member
    from Phila., PA

    I think I've done a pretty extensive search and I'm coming up empty. I want to run the transmission cooling lines on my car. The trans is a TH400, it has 3/8 IFF fittings coming out of the case. The radiator is a Champion with a trans cooler, it has 1/4 IFF fittings in the cooler. I thought it would be easy to run a 3/8 IF hard line and just use an adapter/reducer at the trans cooler. Problem is I am having a hard time finding one. It looks like I could run a reducer into a reducer into a reducer, but that won't look too good. So, does anybody know where I can get a 3/8 IFF to 1/4 IFM fitting? Or, is there a better solution to my dilemma that I am missing. If at all possible I would like to stick with original looking hard lines. I'm not very familiar with AN, IF, UNF, NPT etc., so if I sound like I don't know what I am talking about, it's because I don't:D Thanks in advance for the help!
     
  2. They have 3/8x1/4 compression fittings.
    if you are using the green coated line you'll need to clean it off on the end
     
  3. Mat Thrasher
    Joined: Nov 5, 2007
    Posts: 1,168

    Mat Thrasher
    Member

    Can't you just change the fittings coming out of the trans to 3/8" inverted flare? I changed mine out to 3/8" NPT x -6 flare so I could run AN line.
     
  4. chopper526
    Joined: Sep 12, 2010
    Posts: 252

    chopper526
    Member
    from Phila., PA

    Thanks. I'll take a look at compression fittings, 31Vicky.
    Sorry, Mat, I should have made clear the fittings are welded into the trans cooler. So I need a fitting to thread into the cooler.
     

  5. squirrel
    Joined: Sep 23, 2004
    Posts: 55,933

    squirrel
    Member

    Most 400s use 5/16" flare fittings, and 5/16" lines, most radiators do too.

    I would double check the size of the fittings on the radiator, and see about finding some smaller fittings for the trans, and run 5/16" line. If the radiator really is 1/4" IFF, then see if you can find a hose barb that size and use rubber trans cooler line at that end.
     
  6. Hot Rod Chris
    Joined: Mar 31, 2011
    Posts: 464

    Hot Rod Chris
    Member

    Its a 5/16 line. It should thread into the adapter on the Trans already. If the cooler is 1/4, u a 5/16 rubber line to connect it.
     
  7. HawgHead
    Joined: May 10, 2012
    Posts: 48

    HawgHead
    Member

  8. Mat Thrasher
    Joined: Nov 5, 2007
    Posts: 1,168

    Mat Thrasher
    Member

    Your're fine I knew what you meant. I was talking about changing fittings on the trans to 1/4". I have the same rad in my truck and just looked and it does have 1/4" inverted flare. Which seems kinda small to me. What about drilling and retapping the bungs on the rad to 1/4 NPT? Then you could run any size line you want.
     
  9. dave lewis
    Joined: Dec 12, 2006
    Posts: 1,378

    dave lewis
    Member
    from Nampa ID

    Squirrel...yesterday I went to look at a 69 buick wildcat ( I know o/t !) but a real nice car anyway ...430 t400 trans...

    Suprised to see 3/8 " trans lines !

    Too bad it has been parked 1000 feet from the ocean for the last 10 years. Rust has won the battle.

    Dave Lewis
     
  10. CutawayAl
    Joined: Aug 3, 2009
    Posts: 2,144

    CutawayAl
    Member
    from MI

    I don't know about the TH400, but in many automatics the feed to the cooler is the bypassed oil from the torque converter oil supply pressure regulator. If that line is too restrictive pressure will rise in the converter and cause the input seal to leak.
     
  11. squirrel
    Joined: Sep 23, 2004
    Posts: 55,933

    squirrel
    Member

    I've seen the larger lines on other early BOP 400s
     
  12. chopper526
    Joined: Sep 12, 2010
    Posts: 252

    chopper526
    Member
    from Phila., PA

    Thanks for all the help, guys. They are definitely 3/8 lines, so what I decided to do is use a fitting from Speedway that will reduce the 3/8 inverted flare to 1/4 pipe thread. One of the guys on here told me 1/4 NPT and 1/4IF are the same thread, just that one is tapered and that, for my purposes, I can screw them together. If that works, great. If not, I will tap the radiator out like Mat Thrasher suggested. Then I will use 3/8IF brake line from trans to cooler.
     

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