General trans?

Discussion in 'The "Juice Box"' started by Donuts & Peelouts, Aug 15, 2017.

  1. Donuts & Peelouts

    Donuts & Peelouts Life's 2 Short. Live like it.

    Still haven't decided. But thanks everyone. Sometimes I just reread this thread over and over. I ended up with a 430. I'm leaning towards the sp400 if I can source a 67. Don't know how much an adapter for a Nailhead sp to bop pattern is. I've been keeping my eyes peeled for a free RV with a gear vendors unit. I could get bop th400s for 50$ in my area. Thanks for everyone's time again.

    Since my last post I finally understand rear gearing so thanks again
     
  2. TexasT

    TexasT Texas, where are you from

    if you can get the th400 with the bopc bell housing for $50 that is the way I would go. A new set of rubbers and some clutches and maybe some steels and you are set. Then you can keep the feelers out for the 4l80e or the gv of unit to make it "nice" . In the mean time you can enjoy the ride.
     
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  3. Donuts & Peelouts

    Donuts & Peelouts Life's 2 Short. Live like it.

    Thanks T. I might just do that. Here's a picture of my non mobile Buick haha. Screenshot_20171126-102247.png

    Look out for a new thread I'm going to do in the future I don't know when but it's going to be about the motor mounts on my Skylark because the guy before me converted them into Chevy mounts I have pictures. Going to need some help there too. Hey man thanks for everything.
     
  4. TexasT

    TexasT Texas, where are you from

    car looks awesome. Luv me some square body mid sixties Buick mid size. I'm looking forward to you getting it on the road and driving it. Keep at it.
     
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  5. FJM568

    FJM568 Well-Known Member

    I think a TH400 can be converted to a SP400. Someone correct me if I'm wrong. I could swear I read that somewhere here.
     
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  6. Donuts & Peelouts

    Donuts & Peelouts Life's 2 Short. Live like it.

    I'll look into that, thanks
     
  7. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Yes, the difference is the front pump, input shaft, and converter. It also helps to swap in a later valve body but that isn’t absolutely necessary. The only other thing is there is a passageway in the case that gets blocked. 71stagegs just converted his S/P to fixed pitch. He may want to sell the parts for anyone who is thinking of doing this.
     
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  8. BRUCE ROE

    BRUCE ROE Well-Known Member

    My preference is to take an early 70s TH400 and convert it to switch
    pitch. This gets you a (usually more responsive) later valve body, the
    very available filter and pan, and the case protection ring behind the
    internal center support. It also solves the nailhead pattern or lack of
    a speedo output on an Olds. The 70 Cad trans in my 77 Delta came
    with an extra clutch disc in the direct clutch. Bruce Roe
     
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  9. Donuts & Peelouts

    Donuts & Peelouts Life's 2 Short. Live like it.

    Ok made up my mind, going with a Switch Pitch th400.

    Bruce when you say early 70's, when would be the cut off year... 74,75?

    My plan is to build up a switch pitch th400 inside of a 70s th400. I'm keeping an eye out 4 switch pitch th400's aswell as early 70's th400 to piece together what I need. Thanks.
     
  10. Donuts & Peelouts

    Donuts & Peelouts Life's 2 Short. Live like it.

    Going to the junkyard right now to look at a 65 Oldsmobile Delta 88. It should have the switch pitch th400 in it. You think it's best to just get the parts I need within the trans like the converter front pump and that other thing or should I just take the whole transmission home
     
  11. BRUCE ROE

    BRUCE ROE Well-Known Member

    I don't have a year by year comparison, but they started putting in things like
    plastic and teflon at the end of the 70s, and around 1980 the required metal
    containing the SWP oil passage disappeared from the case. With emissions
    req coming in, the mid 70s valve body may not be ideal. A trans from a big
    block (like my 70 Cad in my 77 Olds) might have the extra 6th clutch disc.

    A 65 Olds has the SWP parts, but a long tail, no center support case protection
    ring, and no speedo output in the case. No problem if moving SWP parts to
    a later case, which also has the slightly deeper pan with common filter.

    Some say pop the splined SWP input shaft out and drive it into your later
    clutch pack. I figure those friction fits won't take many cycles, so I carry
    that clutch pack with its SWP shaft intact, to the building trans. Bruce Roe
     
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  12. Donuts & Peelouts

    Donuts & Peelouts Life's 2 Short. Live like it.

    Thanks for helping me out Bruce, I need more time understanding the innards of a auto trans before I can completely understand you and hold a conversation about it. To my understanding the crankshaft turns while in drive with the flexplate bolted onto the converter. At idle it's just enough force to twist the driveshaft, differential then wheels. When gas is applied and rpms reach a certain level the trans shifts itself from the pressure of the hydraulic fuild to second. That's where I'm lost, im going to go watch come trans mission videos and get back to you.

    And stall? Is stall the moment right before the trans shifts up.

    I don't get slippage either, is that when your wanting to shift or expecting to shift but you have to let off the gas so it can shift?

    A transmission guy once told me I asked to many questions and that all I needed to know was how to put one back together but I would like to know.

    When a car is neutral compared to drive what is the relation of the piolet bushing to the crankshaft.. What I'm asking is how engine and transmission connected and disconnected?
     
  13. TexasT

    TexasT Texas, where are you from

    look in YouTube for a video on how a torque converter works.
    as far as the trans at the yard id just get the whole thing so you don't miss out on getting something you need.
    that converter is bolted to the flex plate and is turning any time the engine is running. This is how the trans pump develops pressure as the converter is attached to the pump rotor and also spins any time the engine is running. This provides trans fluid to the converter and the rest of the trans. The converter is a pretty nifty piece as you will see in the videos.
     
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  14. Donuts & Peelouts

    Donuts & Peelouts Life's 2 Short. Live like it.

    Thanks TexasT.. I just want to understand it too. I'll be in touch
     
  15. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Stall speed is a very misunderstood topic. A torque converter consists of 3 basic parts, turbine, stator, and impeller.

    Torque+Converter+Construction.jpg
    Stall speed is defined as the maximum RPM the engine can turn the turbine when the impeller is held stationary. There are alot of factors that influence stall speed. Inside the converter, the fin angles of the turbine, stator, and impeller. The switch pitch transmissions have a stator that changes the blade angles. The car weight, and gearing, as well as engine torque all influence stall speed. In the real world, stall speed changes depending on how much power is being applied to the converter. Stall speed will be different at WOT, than it will be at small (cruise) throttle opening. Efficiency is an important term when talking about a street torque converter. With the current state of converter technology, you can have a converter that feels more like a stocker at light throttle, but stalls way up where you need it to when you hammer it.
     
  16. Donuts & Peelouts

    Donuts & Peelouts Life's 2 Short. Live like it.

    LARRY thanks alot for your explanation and pictures. Last night after Texas T told me to watch some videos I did and that video plus your explanation really helped me out. Here is the video for Any one in the future who stumbles across this thread.


    Thanks everyone!
     
  17. TexasT

    TexasT Texas, where are you from

    if it were up to trans shops, we would all be made to think it is just all magic in there. Not to be understood by any but those who practice "the craft" in that shop.
    while it does take some special tools and techniques, a trans overhaul isn't any harder than pulling one out and putting it back in if you ask me. Just know you must keep it clean and it must be just right. Air check those pistons and such because pulling it back out to correct somethin minor that could have been caught on the bench is a major pia.
     
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  18. Donuts & Peelouts

    Donuts & Peelouts Life's 2 Short. Live like it.

    Thanks for the confidence and the tips about the pistons.

    Can you believe I took one step back from going with a th400. And now I'm at the th400 vs 200r4 deliema in my head.

    At first the 200r4 scared me because of the amount of money I see guys throw into it, 2k,3k even 4k.

    And the th400 is cheaper, but the freeway makes me uneasy rolling on a higher rpm.. I could do 2500-2800rpm on the freeway but at 3000-3400 running constant is a turn off for me. Why, been there done that.

    Gearing the rear right for the th400 is an option, but still I would like to know the freeway rpms.

    I at times get told "a 200r4" will live behind a BBB if you don't beat it up.

    But I'm building this car to beat up.
     
  19. Donuts & Peelouts

    Donuts & Peelouts Life's 2 Short. Live like it.

    I'm like a little boy trying to pick what amusement park he wants to go for his birthday at this point hahahaha:(:cool:o_O:eek:
     
  20. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    The major factors you need to consider are engine power and traction. Big power with perfect traction make the most demands of drive line parts. The weak link will be found. A stock 2004R will not last long behind a 455 unless you are "Driving Miss Daisy". So the first question is, exactly what 455 engine do you want to put this transmission behind? Stock 455? What year engine? Modified? We need a power estimate. Second, do you plan on putting sticky tires on this car and launching it? If so, you'll need to spend some money on the 2004R. Probably 3000.00 with a good converter. The 400 in stock form will handle most 455 builds. You can also go the route I took, 400 + Gear Vendors Overdrive. Then there is the 4L80E.
     

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