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Shift Kit....Hard Downshift

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by johnny reb, Feb 5, 2001.

  1. johnny reb

    johnny reb 1/2 ton status

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    After doing some research, I finally found a good tranny shop to rebuild my 700r4. I told them I wanted them to build it strong and to last long. Well, they did the rebuild for around $1500. They put in all the goodies: super servo, superior shift kit, heavy duty torque converter etc. etc.

    Here's the problem though: In overdrive, it shifts fine throughout, up and down. However, in regular drive the downshift from 2nd gear to 1st gear is extremely hard, such as when I'm slowing to a stop. Sounds like the whole driveline is about to fall out.

    Now I've talked to several others that have taken their trucks there for rebuilds and they had nothing but good to say about this place. Mechanic says he's never had this problem before. I'm stumped, he's stumped, and I'm still without my truck. Any ideas?
     
  2. k5king

    k5king 1/2 ton status

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    first off,,,i take it you have a warranty????
    even if you don't i would POLITELY ask them to check out the vavling in the valve body...it seem's like you may have a sticky valve,,don't know why just in drive and not overdrive but this might be the problem,,,,if not tell them you want them to totally re-do the rebuild because you are not satisfied with the quality of work you recieved,,if they are a reputable company they will fix this problem for you no matter the cost to them....
    you should not have to pay a dime to fix something they broke or did not rebuild right the first time....
    just my.02


    ANYBODY LOSE THEIR JEEP????????[​IMG]
    I JUST FOUND ONE UNDER MY BLAZER!!!![​IMG]
    [​IMG][​IMG]
     
  3. johnny reb

    johnny reb 1/2 ton status

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    I haven't even got my truck back yet. They said they were done with it so I went to pick it up. I took it for a test drive only to return 5 minutes later and tell them that I wasn't satisfied with the down shift. These guys have been extremely professional and they won't give me my truck back until they have it repaired to my satisfaction. That's why I'm trying to figure out what the problem is with the rough down shift.
     
  4. redbeast

    redbeast Registered Member

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    Hey Jhonny : when you sat super servo do you mean the vette servo or the fairbanks ? If its the vette servo then you remove .125 thnds off the 4th apply piston.. If its the Fairbanks you are going to have to live with it or remove the servo an reinstall the stock one ( I wouldnt )..There is nothen wroung with the trans, he built it jus the way you wanted it (stroung) all the pressures have been modified to help the trans live under some extreme use , so dont expect it to shift like grandmaws pickup.. I have been building these trans for years including the one in my 85k5 it does the same thing when its in the D range instead of the OD range... Hope this helps.. RGee..
     
  5. Wallyb

    Wallyb Registered Member

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    Hey johnny.....you have the exact same problem as mine!!! You ONLY hear it in Drive, and just before stopping or turning right? The guy I bought mine from had the 700r4 rebuilt and said it's done that since he had it rebuilt! Problem is, I haven't found out the problem to it either! If you find the solution to it let me know, please!! Email me at: WallyB_69@yahoo.com

    Thanks, and good luck!

    <P ID="edit"><FONT SIZE=-1>Edited by wallyb on 02/05/01 06:35 PM (server time).</FONT></P>
     
  6. johnny reb

    johnny reb 1/2 ton status

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    I have no problem with the crisp shift from 1st to 2nd gear and from 2nd to 3rd. As a matter of fact, I love the shift kit. My problem is when it shifts down from 2nd to 1st when coming to a stop when in regular drive. Like I said, this only occurs when not in overdrive. If I leave it in OD, it shifts fine all the way through. It doesn't make sense to me why the rough downshift occurs only when not in OD. Is it normal to have an extremely rough downshift from 2nd to 1st when I'm not using OD?
     
  7. Daveytree

    Daveytree Registered Member

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    I wouldn't worry too much about it. My truck did the same thing for six years. When it was finally rebuilt, there was no evidence of any internal abuse. I also had a vette servo in there. Like I said though, six years of faithful service. Granted, my truck went up in flames because of a blown tranny, but that was a result of a faulty rebuild. I never had any problems before that.
     
  8. HarryH3

    HarryH3 1 ton status Author

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    Take a look at the hydraulic circuit diagrams in a tranny service manual sometime and you'll understand why it behaves differently based on the gearshift selction. I know that you'd think that "D" would just prevent 4th gear from engaging, but it also uses different hydraulic circuits for some events than when the gearshift is in "OD". There's a lot of magic going on in those slushboxes! [​IMG]

    <font color=black>HarryH3 - '75 K5</font color=black>
    <A target="_blank" HREF=http://ThunderTruck.ColoradoK5.com>http://ThunderTruck.ColoradoK5.com</A>
     
  9. johnny reb

    johnny reb 1/2 ton status

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    So you are saying that the rough downshift is normal after installing a shift kit? Guy that rebuilt it even took it for a test drive and said that it shouldn't be downshifting that hard.
     
  10. Stoopalini

    Stoopalini 1/2 ton status

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    My TH350 has a shift kit (not sure which one) and it does the same thing.
    There is a pretty loud click when downshifting from 2nd to 1st. It's been doing this ever since I owned it. I'm not worried about it because it is so consistant.

    Now if the click starting getting louder, longer, or started happening at different times, then I would worry; but as long as it's consistant, I'm happy.

    Thomas.

    -- '84 K5 Blazer --
    <A target="_blank" HREF=http://Stoopalini.coloradok5.com>http://Stoopalini.coloradok5.com</A>
     
  11. ftn96

    ftn96 1/2 ton status

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    Johnny, mine is a 90 and it does the same thing. I would classify it as being un-exceptable. but it does get on my nerves on stressful days. But you may want to check for some slop in the rear end. This may be the culprit. As the tranny is all stiffened up now and the rear still may have that common GM slop common with warn out stock carriers. Check it out, it wouldn't hurt. Check to see, or have them check, to see if the carrier center pins wobbles around in the carrier a bit, or see if the spider gears wiggle arund with your fingers. If this is the case, then that may be your peoblem. See when you tighten up one thing, it tends to exagerate or make other smaller things that have been un-noticble or exceptable in the past, to now be very noticable. Call them and ask them if that is a possibility.

    Will work for beer, parts and tools.
    90 Jimi,350/700R4/241/10bolts/4.10's/33's/4"
    <A target="_blank" HREF=http://www.nashvillek5.freeservers.com>http://www.nashvillek5.freeservers.com</A>
     
  12. johnny reb

    johnny reb 1/2 ton status

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    Well, I picked it up last night. Problem solved. They put in a corvette servo and took out the fairbanks. Now it shifts like a champ. Thanks for the help
     
  13. Blue85

    Blue85 Troll Premium Member

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    A lot of 700R-4's did this from the factory. It's already been around on this board a few times. It is usually not even related to the shift kit. I am excited to hear that you got it fixed with nothing but a servo change, but that doesn't really explain why it would do it only in D before. Is the 2-1 downshift even smoother now in OD than it was before, too?

    <font color=blue>"Anytime you tie the Flyers, you are going to have a tight ball game." Buffalo captain Michael Peca</font color=blue>
     

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