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auto tranny upgrade?

Discussion in 'The Garage' started by 84gmcjimmy, Jul 8, 2004.

  1. 84gmcjimmy

    84gmcjimmy 1 ton status

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    Hey, I heard someone mention it before, but I wasn't sure if it's possible. Is it possible to buy something to make the auto tranny shift higher in the rpm's? It would be better for me when I am in the mud. I don't know what RPM the th-400 shifts at, but say it shifts at 3500, is there something to make it shift higher? If so, where can I get one? Or, are they recommended, or are they bad. Thanks /forums/images/graemlins/peace.gif
     
  2. mudhog

    mudhog THEGAME Staff Member Super Moderator

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    you can put in a shift kit like a stage 2 or the stage 3 but the stage 3 you have to manually shift it always. you can also turn in the little screw on the vacuum modulator to make it shift at a higher rpm
     
  3. Ryan B.

    Ryan B. 3/4 ton status GMOTM Winner

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    What tranny is this for? a turbo 400?
    On 350's and 400's they have a vaccum modulator which is the load signal and tells the tranny how late to shift.
    They have ones with red stripes and black stripes, i think the black stripe is heavy duty and will make the tranny shift just a bit later.. you can stick a tiny screwdriver into the opening of the modulator and get some adjustment out of it but it is only good for adjusting the shift points around 3-5mph at most.
    Disconnect that vaccum line and the tranny will probably only shift at close to full throttle and very late (high rpm).
    If you have a th350, the kickdown cable needs to be adjusted so when you're on the gas hard it raises tv pressure and makes it shift later. a good way to tell if you have it adjusted close is you should be able to do a 3-1 downshift by hammering it at around 25-30mph. WOT should be pulling on the kickdown cable all the way.
    The th400 is electronic kickdown.
    A shift kit gives you much snappier solid shifts and will raise the shift a bit points also.
    If your kickdown is adjusted properly and it still shifts too early then yes, you could go to the junkyard and pull a governor out the side of the tranny case and play around with trying different ones and see how it adjusts shift points... i think jegs magazine has governor recalibration kits with different weights so you can adjust it to meet your needs?
     
  4. 84gmcjimmy

    84gmcjimmy 1 ton status

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    It's going to be a turbo 400. Shannon, where can I read more/look at these "Stage 2/3 kits" from?
    Ryan, I will try what you suggested when I get everything hooked up. Thanks for the help /forums/images/graemlins/thumb.gif
     
  5. Ryan B.

    Ryan B. 3/4 ton status GMOTM Winner

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    I would say if your gonna be mud running and racing, you'll want a shift kit anyways and that might raise your shift points where you want em.. B&M, A stage 1 is mild, stage 2 is hard and really solid, that is what i put in my truck, chirps my 35's going into second a lot. Stage 3 is full manual where you must shift all the time.
    Some of the kits come with a different spring or valve that you put in the valve body, maybe a stronger shift valve spring so it'll shift later. If the stage 2 kit doesn't raise your shift points where you want em, you can always just pull the shifter down and hold it in gear till 5,000 and shift it manually. /forums/images/graemlins/peace.gif
     
  6. Calclips

    Calclips 1/2 ton status

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    Buy a B&M light truck megashifter. If you want it to run tame you can just pull it back into regular drive. Or, when you wanna hold the gears out and shift it manually... just pull it all the way back into ratchet mode.
     
  7. 84gmcjimmy

    84gmcjimmy 1 ton status

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    This will be a mudbogger and rockcrawler.
    Thanks, I will take a look for the B&M shift kits in a few minutes. /forums/images/graemlins/peace.gif
     
  8. mudhog

    mudhog THEGAME Staff Member Super Moderator

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    go with a transgo stage 2 shift kit the b&m ones are junk and get the smallest modulator you can i believe it has a red stripe on it. right where the vacuum line ataches to the modulator if you look in there you will see a small screw you can turn it to change the shift points.
    more info on the transgo shift kit
     
  9. 84gmcjimmy

    84gmcjimmy 1 ton status

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    Okay thanks, I will take a look at that site later, I gotta get outside working again.
     
  10. Ryan B.

    Ryan B. 3/4 ton status GMOTM Winner

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    Yah for a th400 i had a B&M stage2 working good, and then changed it to stage3 and seemed like it didn't work right... /forums/images/graemlins/doah.gif i took that crap out and put in a tci reverse shifting full manual valve body.. /forums/images/graemlins/peace.gif this is in my big block camaro.With my high stall converter and low vaccum, it was kinda searching for gears leaving it in D. /forums/images/graemlins/rotfl.gif now i have to always row through the gears with my automatic. /forums/images/graemlins/dunno.gif /forums/images/graemlins/screwy.gif still lights em up into the next gears but not as harsh 1-2 shift now with the manual valve body compared to the stage 2 but extremely positive and firm shifting 1-2 and 2-3. No more burning clutches. /forums/images/graemlins/grin.gif
    So i guess for your th400 if just doing a shift kit i'd probably reccomend a transgo or something besides b&m.
    For my k/5's th-350 i put in a B&M stage 2 and i'm loving it. /forums/images/graemlins/dunno.gif
     

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