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clutched automatic?

Discussion in 'The Garage' started by sled_dog, Jan 1, 2007.

  1. sled_dog

    sled_dog 1 ton status

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  2. diesel4me

    diesel4me 1 ton status Premium Member

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    Only seen a few...

    I've seen some like that used in drag racing..the clutch is more like an "on-off" switch than a clutch really..

    I don't know too much about them,other than some use "air shift" to upshift the valve body rather than the usual govenor and modulator we are used to seeing..I was suprised the lowly "Powerglide" tranny is the most used one in dirt track racing and rail dragsters!..:eek1:
     
  3. sled_dog

    sled_dog 1 ton status

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    why is that surprising? They can be built to take MASSIVE power, have low parasitic draw, and are compact transmissions. Besides in those 2 forms of racing, gear options are pretty unimportant. Most circle track racing you stay in one gear the entire way around the track.
     
  4. HarryH3

    HarryH3 1 ton status Author

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    B&M used to sell Clutch-o-matic transmissions many years ago.
     
  5. southernspeed

    southernspeed 1/2 ton status GMOTM Winner

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    That's a weird one! Must be for some sort of circle track racer eh? Midgets do you call them??
     
  6. sled_dog

    sled_dog 1 ton status

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    They made 2. The "ClutchFlite" and the "TurboClutch". Torqueflite and TH400s respectively. Thats about the majority of what I have found. That and they aren't THAT strong. Just what guys did back in the days before Transbrakes.
     
  7. Corey 78K5

    Corey 78K5 1 ton status

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    One of my old Hot Rods or Car Crafts from back in the 80's had an article on how to do it.........
     
  8. JEBSR

    JEBSR 1/2 ton status

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    They work well in a drag car as well as dirt track. You get the quick gear changes of an auto without using the clutch and the direct connect of a standard trans. Best of both worlds.
     
  9. beater_k20

    beater_k20 Banned

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    uh, Bob, you're an older guy right? they've been using 'glides for that stuff since before you were old enough to drive...
     
  10. dontoe

    dontoe 3/4 ton status GMOTM Winner

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    I had a '63 Impala with a Poweglide. I could actually push it off to get it cranked. Don't know any other auto you can do that with. :D
     
  11. diesel4me

    diesel4me 1 ton status Premium Member

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    yep...I'm old!..

    I had known about those clutched automatics,just never really did get into the hows and whys of doing that to one...I thought they were cool,kind of strange that you could eliminate the converter,and still have it work!..

    I owned at least 4 Chevy's with Powerglide tranny's..a '67 Impala,'68 Caprice Estate Wagon,73 Chevelle,and my 72 Chevelle Wagon all had one..never had a lick of trouble with them,but I hated having only 2 speeds!..my friends ribbed me,saying they had only 2 ranges,"Scream" and "Bog"!!..they made a weird siren noise at idle in park,kinda like a turbo..

    GM had another version called a "Turbo-Glide"..I had one friend who owned one, in a '69 Camaro..identical to a Powerglide externally,but it had no automatic shifting provisions--YOU had to shift it manually!..if you didn't shift into "low" at a stoplight,it would take off in "drive",and slip the torque converter to make up for the lack of pulling power...

    I think you could only push start the cast iron Powerglides,and maybe some of the early aluminum case ones--they stopped putting rear pumps in them after about 1966???--and NO automatic will push start without one--you cant spin the input shaft with the driveshaft, if no pump is there to push the fluid..:crazy:
     
  12. sled_dog

    sled_dog 1 ton status

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    All torque converters slip to increase power no matter what the gear selection. It is the nature of them. Until lock-up converters(TH350, 700R4 and newer transmission, not sure if there was a lock-up TH400) they always slipped, even in 3rd gear(1:1). Its the nature of the beast. Modern transmissions apply torque converter clutch at different times to limit slippage, mostly while lightly cruising in 1:1 or overdrive gears.

    Not to say the main reason for torque converter "slip" is torque multiplication, but it is a function of it.
     
  13. beater_k20

    beater_k20 Banned

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    dont forget the 2004R too, WAY better trans than the 700R4.

    IIRC the TH400 used one too, but it was called Switch Pitch or something along those lines. i could be mistaken though, as i've never really messed with a TH400.
     
  14. 3 on the tree

    3 on the tree 1/2 ton status

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    Buick used the dual pitch convertor. You can still but the kit to have 2 different pitches with these, from a toggle switch.

    Early 727s also had the rear pump, so you could push start them.
    BTW, a Clutchflite shifts really HARD. I pitted for one in HS. C/Altered Bantam body. Tunnel ram Hemi on alky, with a Clutchflite. I got to make one pass in it. Scared the crap outta me!!!!!! The frame was round tube. The motor mounts were Intl truck rods. The owner had different length d-shafts, just loosen the caps on the mounts, and move the drivetrain back or forward for better traction.:D
     
  15. buffblazer

    buffblazer 1/2 ton status

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    well in drag racing you only really need two speeds and you can use the clutch like a tranny brake on autos to get the revs high and then flick the switch and BANG!!! it engages and then your off, just like when you dump the clutch. thats how almost all (im not gonna say every one because im not shure) use some sort of tranny brake or clutch system to get the most power without leaving the line. but i may be wrong........
     
  16. ntsqd

    ntsqd 1/2 ton status

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    A variation of the "CrowerGlide" which used a Crower slipper clutch in place of the converter. Those clutches were very much NOT an on/off switch. You could sometimes idle with the trans in gear and the clutch engaged. All depends on how the pre-load springs and the counter-weights were set up. A good slipper clutch tuner is worth his weight in gold around the drags.

    I could always tell when they were the Super Comp cars. You'd hear a BBC wind up into the Stratosphere andthen bog and grunt after the one & only shift. And there we were trying to make a Boss 302 leave like a 4.5" stroke. :doah: :doah:
     

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