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.

Replacing a TH350 with a 700R4

Discussion in 'The Garage' started by MontanaLifted, Sep 3, 2002.

  1. MontanaLifted

    MontanaLifted 1/2 ton status

    Joined:
    Aug 27, 2002
    Posts:
    171
    Likes Received:
    0
    Sorry fella's I can't find my original post so I'm going to post it one more time.
    --I want to put a 700R4 in my '77 rig. I've heard rumors about things that you need to do for vacuum pressures or something. My rig is all mechanical and I've been told that if I just drop a 700R4 straight in I'll burn up the overdrive.


    Any wisdom that could be passed on would be great.
    /forums/images/icons/confused.gif
    Thanks,
    -MontanaLifted
     
  2. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

    Joined:
    Dec 14, 2001
    Posts:
    22,060
    Likes Received:
    69
    Location:
    Pleasanton, CA.
    Basically you need to buy a kit that will allow the convertor to lock and unlock, and also you must hook up the TV cable which is what makes the tranny shift correctly. The 700R4 uses throttle pressure to make it shift unlike your TH350 using a vacuum source. I am guessing that you have a 203 x/case in your truck so you will need to buy the Advanced Adapters output shaft or use a spacer along with your current adapter plater. You will also need to modify your existing x/case shifter since the 700R4 is 1 7/8" longer than your existing TH350. You will also need to lengthen your front driveshaft and shorten your rear driveshaft. You will need to move the crossmember back 1 7/8" also. I think I have covered everything you will need to do, I could be missing something and I am sure that someone else will chime in and list whatever I may have forgotten.
     
  3. bryguy00b

    bryguy00b 3/4 ton status

    Joined:
    Apr 7, 2002
    Posts:
    5,587
    Likes Received:
    0
    Location:
    Rochester, N.Y
    seems to me its almost not really worth it..
     
  4. i_4x4

    i_4x4 1/2 ton status

    Joined:
    Feb 20, 2000
    Posts:
    359
    Likes Received:
    0
    Location:
    Brighton, Colorado. USA
    I put a 700r4 in my '85. Yes it did come w/ a 700, but it had a th350 when I got it. When I switch trannies not knowing if the original wiring was still functional, I had my tranny builder make it fully hydrolic for lock up. No wiring or switches needed. He CHARGED me an additional $25. Hope this helps. Ed
     
  5. MontanaLifted

    MontanaLifted 1/2 ton status

    Joined:
    Aug 27, 2002
    Posts:
    171
    Likes Received:
    0
    What if I had a NP208 transfer case?
    Will the splines match?
     
  6. Chris_T

    Chris_T 1/2 ton status

    Joined:
    Mar 17, 2001
    Posts:
    718
    Likes Received:
    0
    Location:
    Saskatoon, SK
    With a 208 it should be a bolt up
     
  7. MontanaLifted

    MontanaLifted 1/2 ton status

    Joined:
    Aug 27, 2002
    Posts:
    171
    Likes Received:
    0
  8. Chris_T

    Chris_T 1/2 ton status

    Joined:
    Mar 17, 2001
    Posts:
    718
    Likes Received:
    0
    Location:
    Saskatoon, SK
    A 208 from behind a 700, right? Or is it behind your 350 now?
     
  9. MontanaLifted

    MontanaLifted 1/2 ton status

    Joined:
    Aug 27, 2002
    Posts:
    171
    Likes Received:
    0
    NP208 mated up to my TH350 right now.
    /forums/images/icons/crazy.gif
     

Share This Page