Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

Taming a shift kit?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by ftn96, Apr 10, 2002.

  1. ftn96

    ftn96 1/2 ton status

    Joined:
    Sep 26, 2000
    Posts:
    3,238
    Likes Received:
    0
    Location:
    Nashville Tn
    After getting this TCI steet fighter set up and going with all the other madness I had going on, I have found that this SOB is gonna end up causing me problems with u-joints or the vertebra's in my neck. GOD this thing slams second gear. I can feel the side walls of the TSL's flexing everytime it shifts.

    I've adjusted the TV back just a notch to see if that helped, and I'd say that it did just a "TAD" but not enough to really mention. What all would be involved to lighten it up just a "TAD", short of replacing the whole shift kit? Or is there not any other way? It has the corvette servo. Would swapping that out with a stock unit help at all?

    Thanks,
     
  2. ftn96

    ftn96 1/2 ton status

    Joined:
    Sep 26, 2000
    Posts:
    3,238
    Likes Received:
    0
    Location:
    Nashville Tn
    Talked to TCI. They said I could replace the pressure regulator spring with a stock one. Is this a drop the pan there's the spring sorat deal, or am I going to have to drop the whole valve body?
     
  3. DesertDueler

    DesertDueler 1/2 ton status

    Joined:
    May 23, 2001
    Posts:
    3,106
    Likes Received:
    0
    Location:
    Phoenix, AZ
    You will ave to dro the valve body. Its not hard to do, just be careful as to not loose the check balls.
     
  4. ftn96

    ftn96 1/2 ton status

    Joined:
    Sep 26, 2000
    Posts:
    3,238
    Likes Received:
    0
    Location:
    Nashville Tn
    Is the real name of this spring the : 1,2 accumulator spring ??
     
  5. reddog64

    reddog64 1/2 ton status

    Joined:
    Nov 9, 2000
    Posts:
    3,325
    Likes Received:
    0
    Location:
    Federal Way, Washington
    go to my web site and read my write up and download the directions i have posted... in pdf format.. it shows you waht spring there talking about!
     
  6. ftn96

    ftn96 1/2 ton status

    Joined:
    Sep 26, 2000
    Posts:
    3,238
    Likes Received:
    0
    Location:
    Nashville Tn
    KEWL! Now I know which one thye are talking about. Thanks RED! Im gonna see if I can find one today. /forums/images/icons/smile.gif
     
  7. ftn96

    ftn96 1/2 ton status

    Joined:
    Sep 26, 2000
    Posts:
    3,238
    Likes Received:
    0
    Location:
    Nashville Tn
    Well, after refreshing my memory adn talking to TCI and the dealer, the pressure regulator spring is in the pump, which would mean the whole tranny would have to come out. But the guy at TCI, was talking about something to do with an accumulator which would be the pan. So did I just get ahold of a morron or what?
    Well, I called TCI again and talked to another guy and he confirmed that the spring Im in search of is in the pump. POOP!
    That means the tranny would have to come back out. /forums/images/icons/crazy.gif
    Maybe I'll learn to live with it and start driving around with a neck brace or something!!! /forums/images/icons/laugh.gif
     
  8. Blue85

    Blue85 Troll Premium Member

    Joined:
    Jul 26, 2000
    Posts:
    9,086
    Likes Received:
    487
    Location:
    Grand Rapids area
    What transmission is this? 350 or 700?

    I feel your pain! I am fighting this same problem right now with my 700 since my most recent tear down. I think people in other cars know when I shift into 2nd. It's great at WOT, but for easier driving, it's sorta ridiculous. I am planning on just taking a shim out of the 1-2 accumulator or switching to a lighter spring. I don't want to change my pump pressure regulator spring, because that would soften all of my shifts and the rest are about perfect.

    But whatever you're planning, it won't require the tranny to come out. At worst it will mean removing the valve body. The 1-2 accumulator spring or the pump pressure regulator can be done with valve body in place.
     
  9. ftn96

    ftn96 1/2 ton status

    Joined:
    Sep 26, 2000
    Posts:
    3,238
    Likes Received:
    0
    Location:
    Nashville Tn
    I've got the 700. The 700 doesn't have a pressure regulator in the valve body. It has 1 and its in the pump. I was thinking about the 1-2 accumulator too. But the guy I talked to at TCI said that wont work. Said it would cause erratic shifting. But who knows if that guy was as bad as the first guy I talked to or if he was some bozo they hired from Mcdonalds.

    I too, like you would like to leave 2-3, 3-4 the way they are. PERFECT. But the 1-2....man I start bracing myself for it. I even have started to get use to where its gonna hit and let off the gas right before hand. That works great if you can time it perfectly, but that varries for every change in RPM. I dont know if I can memorize that many shift point variables. /forums/images/icons/laugh.gif

    If you figure something out, let me know. Im gonna do some more studying in the meantime!
     
  10. sinchphoto

    sinchphoto 1/2 ton status

    Joined:
    Mar 7, 2000
    Posts:
    366
    Likes Received:
    0
    Location:
    Southern California
    I adjusted my shifting by using a pressure guage on the tranny housing. As soon as pressure rises you lock in the cable. I now get a verry smooth transission between 1-2 gear. But now my 2nd gear seems to last longer before shifting into 3rd. I'll keep messing around with it and see what happens.
     
  11. Blue85

    Blue85 Troll Premium Member

    Joined:
    Jul 26, 2000
    Posts:
    9,086
    Likes Received:
    487
    Location:
    Grand Rapids area
    What I meant about the pressure regulator valve is that you can pull the valves out of the oil pump without taking the tranny and pump out (at least I'm sure for the converter clutch valve).

    But I don't see why messing with the 1-2 accumulator wouldn't adjust the harshness of the shift. That is it's purpose: to dampen the shock of the oil that engages the servo. It shouldn't have any effect on shift points or the feel of any other shifts.

    Just FYI, I am using a Corvette servo, in case that is a common thread. If I have luck, I will let you know what I did. The raptor site says that the bigger servos give a firmer 1-2 shift, but I am not clear as to why. The bigger servo should be slower since more fluid has to move to engage and disengage it. It should have more force on the band, though and maybe that extra force is what makes the shift happen faster.
     
  12. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,980
    Likes Received:
    189
    Location:
    Roy WA
    I'm pretty sure the force acting on the piston is greater with the larger surface area. The servo presses a pin, which "clamps" the band onto one of the drums, to stop it. The harder you can clamp it (and the faste ryou can stop it) the more positive and strong the shift will be.

    If that band slips, you will burn the clutch and perhaps warp the drum from heat. Very common (at least in the similar 200-4R) when putting a lot of horsepower through a tranny not really set up for it to have 2nd gear slip, or have a "flare".

    The pin length is adjustable as well, and is supposed to be checked at least on rebuild. I *think* pin length can be changed when changing the servo, but not positive on that one.
     
  13. Blue85

    Blue85 Troll Premium Member

    Joined:
    Jul 26, 2000
    Posts:
    9,086
    Likes Received:
    487
    Location:
    Grand Rapids area
    The pin length can be changed just be pulling out the servo, but I'm not sure how to determine exactly what length you need that way. You don't adjust it, though, you just get a different length pin. They are available in different sizes.

    Maybe I could try putting my stock servo back in to see the difference, but my tranny likes to flare in the 2-3 shift with a stock servo because it releases too fast (before the 3-4 clutch is engaged, possibly due in part to the 10 little release springs I put in it)

    And of course a bigger piston provides more force. That is hydraulics 101. But if the band slips, you will burn the band, not a clutch.
     
  14. ftn96

    ftn96 1/2 ton status

    Joined:
    Sep 26, 2000
    Posts:
    3,238
    Likes Received:
    0
    Location:
    Nashville Tn
    My street fighter 700 also has the corvette servo. You and D sound like you all know a little more about this than I do. I was just a hydraulics mech in the Navy. So I just have hyd. knowledge, not that much but enough to be dangerous. /forums/images/icons/laugh.gif. My grandfather jnows a pretty good tranny guy. Im gonna quiz him and see what he says. Keep me in the loop[ though. Im tired of hearing my CD player skip everytime I hit 2nd gear! /forums/images/icons/shocked.gif
     
  15. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,980
    Likes Received:
    189
    Location:
    Roy WA
    Sorry, was using band/clutch interchangeably...even though the band is faced with (typically) the same material as the clutches in the clutch packs. Yes, I meant band.

    Well, with the 200-4R there is a tool, but basically you measure how far the pin moves with X amount of pressure applied to it. I think maybe I rigged up a dial indicator on mine, but its been a long time. There are 4 lengths of pins for the 200, assume probably about the same for the 700. But you adjust the apply by changing out the pins.
     
  16. Blue85

    Blue85 Troll Premium Member

    Joined:
    Jul 26, 2000
    Posts:
    9,086
    Likes Received:
    487
    Location:
    Grand Rapids area
    So these guys are all recommending that you change the pressure regulator spring for the main line pressure. That is in the pump. I guess that is based on the assumption that the 2nd gear servo essentially sees line pressure and not TV pressure. Hmmm. I still think that would change all of the shifts. I'm still gonna mess with the 1-2 accumulator first. After that, maybe I'll try the stock servo again. I am not sure if changing to a shorter pin is a good idea or not. I won't be able to get to any of this until Saturday.

    If you want to try tuning the accumulator, it is the big cup-like protrusion that sits to the rear of the valve body. It is held in by 1 long bolt and 2 short bolts. When you take them out, the accumulator cover, piston, spring and any spacers will all be free. The 2-3 accumulator is directly above this and it's spring may push down that corner of the seperator plate, but that is fine as long as you don't loose any check balls, which you probably won't. You can switch to a weaker spring or just remove any spacers on the shaft that came with a shift kit. (You may have to pull the piston out by one of it's ears with some pliers.) This should affect nothing but the 1-2 and 2-1 shifts and can be tuned by trial and error. The only thing that happens for the 1-2 shift is the band apply, so you don't have to worry about any flare or binding from incorrect crossover-that's only a concern for the 2-3 shift in a 700.
     
  17. Blue85

    Blue85 Troll Premium Member

    Joined:
    Jul 26, 2000
    Posts:
    9,086
    Likes Received:
    487
    Location:
    Grand Rapids area
    OK, I'm a dork. I was just thinking about this and remembering that I had said that the 2-3 accumulator was up there. Well, it's not. a 700 doesn't have one, only a 1-2 and a 3-4. They are each damping the application of the band, one for each of the servo pistons that applies the band. Therefore, the 1-2 acuumulator affects two shifts. It primarily affects application of the 2nd gear servo, but also affects it's release during the 2-3 shift. The 3-4 accumulator will just affect application and release of the band when shifting in and our of overdrive.

    Soooo...Changing the 1-2 accumulator may have a small effect on the 2-3 upshift and 3-2 downshift, but I still think that it is the first place to attack this problem.
     
  18. Blue85

    Blue85 Troll Premium Member

    Joined:
    Jul 26, 2000
    Posts:
    9,086
    Likes Received:
    487
    Location:
    Grand Rapids area
    OK, mine is solved and hopefully the same thing will work for you, too. I popped open the 1-2 accumulator this afternoon and pulled out the 5/8" long spacer underneath the piston. I then reassembled it with same spring (white). All this did was remove preload from the accumulator spring and allow more travel distance. Now the 1-2 shift is much softer and it seems to vary with throttle about how I want it to. When I hammer it, I want to feel a firm shift (which it does), but if I want to just lollygag around, I want it to be fairly smooth. Now if I'm really easy, I can hardly feel the 1-2 shift.

    The 700 never came with a spacer in there, they just come with shift kits. My SuperTransKit showed accumulator instructions for three levels: Normal, Heavy Duty/Towing and Street/Strip. The Normal uses no spacer, the Heavy Duty uses the 5/8" (which is why I put it there to begin with, two years ago) and the street strip spaces out the entire travel distance of the accumulator piston and takes out the spring! That seems crazy to me, but maybe in a drag car, you just want it to bang as hard as possible.

    What I can't figure out is how I ran so long with the spacer and the 'Vette servo with no problems. Then two weeks ago, I tore the tranny down again to find my "metal maker" and put everything back just how it came apart, other than fixing my problem. Since then it has had the big bang 1-2.

    So anyway, I think it's perfect now. After I have the T.V. valve train tuned perfectly, I will decide if I want to cut down a spacer for the 1-2 acc. to run 1/4" or so or if it is right just as is. Too hard to call after only a couple of miles...

    I just thought I would share to encourage you to try the same thing. You will most likely find a similar spacer. If not, you can always change the spring before resorting to pulling the tranny to reduce line pressure, which I wouldn't want to do even if it wasn't so much work.
     
  19. Blue85

    Blue85 Troll Premium Member

    Joined:
    Jul 26, 2000
    Posts:
    9,086
    Likes Received:
    487
    Location:
    Grand Rapids area
    Dorian,
    Yeah, I looked in the book and there is a special tool for servo apply depth measurement. It attaches to the transmission case and you put the pin in and use a dial indicator to measure how far it is able to move in and out. If it's outside of the spec, you get a different pin. I assume, though, that you only need to change the pin if you are changing the band, as it may be slightly different. When I rebuilt, I just made some depth measurements with the old and new bands and they were virtually the same, so I just stayed with the original pin.

    And BTW, I'll say that you were right all along, as a band really is a kind of clutch...
     
  20. ftn96

    ftn96 1/2 ton status

    Joined:
    Sep 26, 2000
    Posts:
    3,238
    Likes Received:
    0
    Location:
    Nashville Tn
    cool beans man! I think I'll try it adn see. After Friday's ride in traffic, I have to do something.
     

Share This Page