Transgo 1-2 shift kit hole sizes

Discussion in 'The "Juice Box"' started by 1969RIVI, Jun 20, 2019.

  1. 1969RIVI

    1969RIVI Well-Known Member

    I'm looking for some input on the shift firmness selection. My car is a 69 Riv with 455 & TH400. It is a street/strip car that is mostly used on the street. I usually have a mix of intown cruising (stop&go) and highway driving. I want the shifts to be firm but not neck braking. If I was to follow the instructions I would fall into the "Range#2 & #3" area. I've read online that transgo is pretty conservative with their hole sizing and that drilling "hole A" out to .125 (1/8") and same for "Hole B" or can go up to .140 (9/64")on "Hole B" see attached pic of transgo hole sizing.
     

    Attached Files:

  2. GranSportSedan

    GranSportSedan Puppet dictator, wife has all power

    The transgo level 2 is nearly perfect in my experience. Nice firm shift's when getting on it but not harsh under normal driving conditions
     
  3. 1969RIVI

    1969RIVI Well-Known Member

    Grandsport thats what I'm after. So what did you drill your holes to? .093 for Hole A and B and left Hole C alone?
     
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  4. 1969RIVI

    1969RIVI Well-Known Member

    So I ended up drilling both holes A&B to 0.125 to start with and go from there. I've read numerous threads on this site and various other sites about hole sizes and how transgo is very conservative on their orfice sizing. A lot of the posts are from trans builders and guys with real life experience with these kits. Most of them recomend drilling hole A 0.125 and hole B to 0.140 or more for both. I figured I would start with a little less and go bigger if needed but the "real world" experience with the suggested sizing from Transgo seems to be that alot of people wished they went bigger off the hop and that the shifts were to soft/short. I'll be putting the trans back in tomorrow and hoping to test drive it and see where I'm at.
     
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  5. Smartin

    Smartin antiqueautomotiveservice.com Staff Member

    When I did mine, I went with .125 and wished I went bigger.
     
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  6. 1969RIVI

    1969RIVI Well-Known Member

    Well get back on in there and drill them suckers bigger!! Lol. I'm hoping that I don't have to open it back up, I'll try playing with the adjustable vacuum modulator first but if I can't get the shifts where I like then I'll go in and drill them bigger. Atleast that's betterdrilling them too big and having neck breaking shifts in Walmart parking lot with the kids whining in the back and having to buy a new separator plate ontop!
     
    Last edited: Jun 22, 2019
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  7. Bens99gtp

    Bens99gtp Well-Known Member

    The adjustable vacuum modulator is the help adjust shift points not how firm the shift is.
    There is 3 basic fluid pressure in a tranny, line, governor, mod,
    For an upshift to occur Gov pressure has to overcome mod pressure.
    So to move a shift point up you either increase mod pressure or decrease or delay Gov pressure from getting there
     
  8. 1969RIVI

    1969RIVI Well-Known Member

    Post corrected. I see ok well I may need to go back in there if it's not enough for me then.
     
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  9. scubasteve455

    scubasteve455 Well-Known Member

    1969Riv keep us updated. I have a Trans-Go 1-2 shift too. And have no idea what i’m doing. Want my tranny to shift harder.
     
  10. scubasteve455

    scubasteve455 Well-Known Member

    If you have a TH 400 BB . When your cruising at 30 mph. and punch it and the tranny down shifts to 1st. Does the Trans Go interfer with that process?
     
  11. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    No, it will not.
     
  12. scubasteve455

    scubasteve455 Well-Known Member

    Thanks Larry . So I can put in the (2) valves that are in the kit.
     
  13. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Not sure about what valves they are. I would just do everything but. The other stuff makes the shifts faster and harder.
     
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  14. 1969RIVI

    1969RIVI Well-Known Member

    Steve, I followed everything Ben told me to do in his trans mod thread plus did what the transgo kit said to do except I drilled the hole sizes bigger than what they suggested since I've read that transgo is really conservative on hole sizing. As of right now I love the way everything shifts, it's not too hard but you still know there's a kit in there. Another thing is the 9.5" converter from JW, that thing woke my big ass car right up!! If you want really firm/hard shifts maybe drill up to .138- .140?

    http://www.v8buick.com/index.php?th...-kit-and-a-few-easy-internal-upgrades.342929/

    Here's a link to Ben's thread, it's full of awesome tips!
     
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