Ok, so what exactly do these do to the auto trans?

Discussion in 'The "Juice Box"' started by MR.BUICK, Jan 1, 2005.

  1. MR.BUICK

    MR.BUICK Guest

    I've always wondered this...what exactly does a "shift-kit" do for an auto tranny? I know it's been asked before but I can't remember what they do. Thanks
     
  2. Smartin

    Smartin antiqueautomotiveservice.com Staff Member

    Allows your transmission to shift much more crisp.

    Ever wonder how people can scratch 2nd gear so easily? It's a shift kit. I've even seen guys break the tires loose on a "normal" takeoff on the street....kinda makes me wonder WHY?

    A shift kit is a cheap way to make your car feel a bit stronger though:)
     
  3. MR.BUICK

    MR.BUICK Guest

    Thanks Adam :TU:



    Now all I need to know is how much do they normally cost(an estimate?)?

    Thanks
     
  4. Smartin

    Smartin antiqueautomotiveservice.com Staff Member

  5. MR.BUICK

    MR.BUICK Guest

    Thanks adam. Do they make shift kits for the TH-350? I didn't see one while searching jim's info, although I seen one for a TH-400 for 30 bucks.

    Thanks
     
  6. Steve Craig

    Steve Craig Gold Level Contributor

    What are you giving up, if anything, while gaining a crisper shift?
    Reliability an issue here?
    I always thought our older cars were modified on a give/take relationship.
     
  7. Smartin

    Smartin antiqueautomotiveservice.com Staff Member

    Well, with a transmission with 100k miles, you may be asking for a premature puke.

    I talked to a guy who rebuilds trannies for a living, and he warned me about doing it in even a transmission with 80k miles. Do No:

    I'm still going to do it though:grin:
     
  8. a shift kit changes the flow of flud through the valve body and to the clutch assm.
    very easy to install
    it will not come out of lower gears as long as you stand on the pedal
    you can shift it by letting up on the pedal and pushing it down again
    gives you the opertunity to wind the motor out at a higher rpm and then shifting it.
    if you have a tired trany, do not do this
    the clutch packs will fall apart from screaming the oil through them at a higher rpm
    put a rebuild into the trany and then add it
    lots of fun when you got the local vet guy next to you and you have a sleeper.
    Greg
     
  9. Smartin

    Smartin antiqueautomotiveservice.com Staff Member

    I thought the vacuum modulator dictated shift points...?
     
  10. bignastyGS

    bignastyGS Maggot pilot

    If you decide to put a shift kit in,do yourself a favor and put in a new filter as well as oil(obviously) and also buy a tranny drain plug from B&M (ABOUT 5-6 bucks).This way you only have to remove the plug to drain the oil.Then it makes it alot easier to change the filter next time.No oil bath shampoos.You can get TH350's at most speed shops and I think through Advanced Auto or AA Autoparts,Summit and such.About 30 bucks.It requires you to get into the valve body and switch a few balls around and such.But,it pretty straight forward to do.A couple hours of work.If I can do it you can too.I would also reccomend an aftermarket oil cooler to be safe as well.
    Pat
     
  11. Steve Craig

    Steve Craig Gold Level Contributor

    Good reading here. Reason I asked is that last year we pulled the original tranny from my car, 140k miles. Previous owner had installed a shift kit & we didn't like what we saw. 2 fluid changes prior we saw lots of contamination in the fluid. We figured the tranny was about ready to call it a day, so we yanked it.
    Clutch plates completely bare!!
    Had a complete rebuild done, to factory stock specs.. Builder asked about a shift kit, with a twinkle in his eyes. I stuck with the stock set-up.
    Tranny now so smooth you might think it was a 1 speed unit. Shift point hardly perceptible during normal street driving. Floor it & engage the kick down & it really comes alive!
     
  12. LARRY70GS

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

    There are circuits in the transmission that are there to slow down and soften the shifts. They are called accumulators. A shift kit alters fluid flow to the accumulators, and through the valvebody, to speed up the shifts so they occur faster. It also raises the line pressure in the tranny so the clutches apply with more force. A soft slow shift actually causes more wear because the clutches slip more. Shift points are determined from inputs from 3 sources, governor, vacuum modulator, and detent(downshift) position. The vacuum modulator can adjust minumum shift points(2-3 MPH), and shift feel. The governor controls WOT shift points. The detent cable or electric downshift system also modifies shift point and feel. That's why it's important to have a properly functioning downshift system.
     
  13. Smartin

    Smartin antiqueautomotiveservice.com Staff Member

    How do you modify WOT shift points with the governor? (pretty wide open question there:Dou: )
     
  14. cray1801

    cray1801 Too much is just right.

    Adam, to do that you can either replace the governer weights with heavier or lighter ones or lighten the existing ones. A lighter weight will cause shift points to be later, heavier ones earlier.

    The springs have more to do with the 1-2 rpm in relation to the 2-3 shift rpm. If I recall correctly if you lighten the spring pressure the rpm shift points get more consistant (1-2 rpm and the 2-3 rpm closer to the same).

    First adjust the vacuum modulator then kick-down before you do the weights. The springs are maybe the last thing to fine tune if needed.

    Don't lighten you weights too much at one time, but if can go too far try adjusting the kick-down to go back in the right direction.

    There is a weight kit you can order, but you don't always get weights that fit. This happen to me, so I just modified my existing weights for later shift points.
     
  15. LARRY70GS

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

    B&M Governor recalibration kit

    http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=15697&prmenbr=361

    Adam,
    I used this kit without any problem. If you choose to modify your existing weights, and go too far, you can't go back :Do No: Also the weights pivot on "axles" that are really just penny nails with the ends flattened down. Modifying your governor without the kit, entails cutting the axles, removing material from the weights, and then buying some penny nails, and flattening the ends with a hammer. The kit comes with replacement axles that have "E" clips, so disassembly and weight changes are easy and quick. Getting the shift points the way you want them is trial and error, and alot of fun :laugh: :3gears: I have consistent 1-2 shift points @ 5500 RPM, and 2-3 @ 5400 RPM. I did it with this kit.
     
  16. Smartin

    Smartin antiqueautomotiveservice.com Staff Member

    Thanks guys! Ordering the Governor kit & advance bushing from Jegs today..

    Also ordering a Trans-go kit & filter from JW:bglasses:
     
  17. MR.BUICK

    MR.BUICK Guest

    Thanks guys, this info really helps me out, I was just curious and wanted to know, looks like I got the info and more than what I needed, and Adam, good luck on your "goodies" you're gettting :Brow: :TU:
     
  18. Bernie Steffen

    Bernie Steffen Well-Known Member

    700 r4Transmission

    Anybody know if 700 r4 trans has BOP Bolt pattern. Somebody told me early 80 it was available. Bernie Steffen
    center​
     
  19. LARRY70GS

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

    Don't think so. I don't think a Buick built engine was ever coupled with a 700 R4. Think it has the Chebby pattern. The 200R4 has a universal bolt pattern, or some of them do, as I recall. I think there is an adapter plate you can use to bolt the 700R4 up if you want.
     
  20. MR.BUICK

    MR.BUICK Guest

    Weren't the 200r4's the famous transmission used in the GN's?
     

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