TH400 34 Element Sprag

Discussion in 'The "Juice Box"' started by 1969RIVI, Feb 16, 2019.

  1. 1969RIVI

    1969RIVI Well-Known Member

    What are some good 34 element sprag choices for a TH400 auto? So far I've been looking at TCI and Borgs&Warner units. Anybody have any other recommendations and or feed back on the units stated above?

    Thank you.
     
  2. Bens99gtp

    Bens99gtp Well-Known Member

    Borg Warner
     
  3. 1969RIVI

    1969RIVI Well-Known Member

    Hey Ben do you happen to know the part number for the borg&warner sprag? I found a guy on ebay selling them and would like to cross reference his number to make sure its actually the real thing.
     
  4. Bens99gtp

    Bens99gtp Well-Known Member

    Nailhead Ronnie likes this.
  5. Bens99gtp

    Bens99gtp Well-Known Member

    sometime your can find a good used one from a 4l80e at a tranny shop for less.

    I also like the high energy fictions from the 4l80e in the th400 as well, nice upgrade without going to pricey
     
  6. 1969RIVI

    1969RIVI Well-Known Member

    Thanks Ben that link is actually the same seller I was looking at, only on Ebay. In your opinion is the borg better quality over the TCI? I have a good rebuild kit already that came with red alto frictions and kolene steels, I just need the sprag and transgo 1-2 kit and if I can afford it JW is going to build me a custom converter.
     
  7. Bens99gtp

    Bens99gtp Well-Known Member

    if I recall correctly the direct and forward frictions are the same........and are .080 thick

    the direct steels are very similar to the forward steel minus thickness.

    directs are .090. forward are .077

    but you can add thicker or thinner to get pack clearances correct
     
  8. 1969RIVI

    1969RIVI Well-Known Member

    So I'll have to measure the steels and frictions that came in the kit to determine which are the forwards and which are the directs?
     
    Nailhead Ronnie likes this.
  9. Bens99gtp

    Bens99gtp Well-Known Member

    never used a tci, never had one of these fail in 20 years of use in not only my trans, but all the ones I have built.

    you really dont need to spend money on the trans go kits.

    just drill the the holes in the shift p lik ate to sizes. .110 to .125 I go a little more in my race trans, remove the spring in the valve body in the accumulator in the valve body, remove big the spring in the low reverse servo, and dual feed the direct circuit and it will shift plenty firm for most ppls liking
     
  10. Bens99gtp

    Bens99gtp Well-Known Member

    correct they "should" be different, but are 100% interchange able. I often use different ones to get clearances where they need to be.
     
  11. Bens99gtp

    Bens99gtp Well-Known Member

    the forward pack is not as important to get correct since it's a non shifting clutch, but the direct you will want to keep the clearances as close to .050-.060 as you can get........I think thats the spec off the top of my head
     
  12. 1969RIVI

    1969RIVI Well-Known Member

    Ok that's good to know I'm going to order it! Yes I recall you giving me that info in another thread. This will be my first trans rebuild I'm confident in my skills I just have to educate myself with the correct clearances.
     
  13. 1969RIVI

    1969RIVI Well-Known Member

    My car is a cruiser mostly I do like to play in it and it may see the track the ODD time. I also don't want to snap my kids necks everytime it shifts that's why I figured a happy medium with the transgo 1-2 kit would be my best bet. It has a B&M shift kit in it now and it's alright.
     
  14. Bens99gtp

    Bens99gtp Well-Known Member

    k I though I had. lots of parts just keep them in order when coming out.........
     
  15. Bens99gtp

    Bens99gtp Well-Known Member

    download the instruction from like summit b4 buying and see what it lets you to do b4 buying, I haven't bought a shift kit in 15+ years, I just modify the stk plate by opening the holes in the 2nd and 3rd passesages.......bigger will equal harder quicker shifts .110-.125 is normally plenty for most ppl. in race only I go .140-.150
     
  16. 1969RIVI

    1969RIVI Well-Known Member

    Oh yes for sure I usually take lots of pics on how it looks as it comes apart then bag n tag EVERYTHING as to not get confused on what goes where.
     
  17. 1969RIVI

    1969RIVI Well-Known Member

    Ben, do you know where I could get all the clearances/tolerances specs for the th400 automatic?
    Also I ordered the borgs&warner 34 element sprag it should be here by Mach at the latest
     
  18. Bens99gtp

    Bens99gtp Well-Known Member

    mine are in my chassis service manual, I'm sure there is a step by step rebuild book out there that will have the answers you need. it will also walk you through a tear down inspection and rebuild in order
     
  19. 1969RIVI

    1969RIVI Well-Known Member

  20. Matt69olds

    Matt69olds Member

    I think Borg Warner is the only manufacturer of the 34 element sprag. Pretty sure TCI, B&M, etc but then for repacking and resale.

    A good rule of thumb is .010-.015 per clutch disc. The forward clutch isn’t nearly as critical, as long as there is SOME clearance you will be fine. You can mix and match the thicker .080 direct steels with the thinner forward .065 (I think that’s what they measure) to get the clearance you need. I don’t teally like using all thin steels in the direct clutch, the thicker steels absorb heat better. You can run into issues with the steels getting to hot when hot-lapping at the track.
     

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