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2 speed transmission won't shift

Discussion in 'Chassis & Drivetrain' started by chrisexv6, Aug 1, 2018.

  1. chrisexv6

    chrisexv6 Member

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    So my son broke my toy :)

    Had no forward gear anymore, I could feel binding when I tried to spin the wheels and even after pulling the driveshafts, so I tore open the transmission to see shards of plastic. the 2 speed gear (I think its the only plastic gear inside) had stripped. Not sure why, I figured he did something but whatever.

    Got a new gear, new clutch holder, etc. Put it all back together but it wont shift. The engine winds out and I never hear a shift, if you back off the throttle you can hear gear whine like its still spinning faster than it should be, but again it never shifts.

    Ive mucked with the adjustment point a few times but I never hear any change. The trans is from a Savage 21, but I have not been able to find a good number as to what the stock setting for shift point screw should be. I tried 1.5 turns out from tight and 3.5 turns out from tight with no change.

    Any suggestions? I went to look for an assembled trans for sale, but apparently they are made of gold? $200+ on ebay...wtf?

    Thanks in advance.

    -Chris
     
  2. X

    X Conspiracy of One
    HPISF Staff

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    Sadly, I don't believe there is a "stock" setting in any documentation. Only that counter clockwise gets you an earlier shift, clockwise gets you a later shift. I've looked around for transmissions, nothing really out there. Even the 3-speed is unobtainium.

    If you believe you have fully gone through that adjustment, there are a couple other places to check.

    1. Tune. If the truck is not tuned properly it will not get to the RPM necessary to shift.
    2. Clutch shoes/ springs. If they are warn, not going to get up to RPM.
    3. Slipper clutch. Again, if warn will not get up to RPM. Also, if it is loose the same thing will occur.
     
  3. chrisexv6

    chrisexv6 Member

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    Thanks for the tips!

    It all worked OK until the 2nd gear stripped. Was shifting nice, etc. So I'm guessing its not a tune thing (I didnt touch any needles). Will check the clutch and slipper just for the heck of it too.

    I have a feeling its just the darn screw adjustment but with no good starting point and all indications that its really touchy (per the HPI videos on YouTube) I'm not sure just how long it will take to find just the right spot....especially if I'm supposed to shut the truck down to adjust.
     
  4. olds97_lss

    olds97_lss Well-Known Member

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    I don't shut mine down to adjust it.

    All I can think to do is either go in one extreme or another. Tighten the screw gently until the spring is fully compressed, back it off 1 full turn, try it. Back another full turn, try it. Once you back it off far enough to shift, then you can adjust more finely.

    Is it the old transmission with the thin metal plate on the 2-speed gear or the big hunk of metal for a hub for the pawl to catch? The 21 started with a thin metal plate (76929b) and I think a single pin for the pawl to catch. As engines got stronger, people started ripping the pin out of the 2 speed gear, then they would put in a second pin to try and lessen the impact so the pawl would catch with 50% less distance to travel. Then HPI came out with the hunk of metal (86369) instead of just the thin plate recessed in the gear, which fixed the issue completely.

    Old:
    [​IMG]

    Newer, from my Savage X manual:
    [​IMG]

    If you have the older version, did you happen to forget to put in the pins (86094) from the back of the gear?

    The newer version in my X manual says where a starting shift point is if you look. Looks like the set screw is flush with the lower outside edge of the hole, then screwed in 1.5 turns. They don't show that in the 21 manual. Guessing that setting would be similar for either. Well, depending on your cb/spur. If you running something like 15/52, might want to just screw it in 1 full turn from flush with the outside edge of the hole.

    Whatever you do, make sure to put locktight on the set screw.
     
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  5. chrisexv6

    chrisexv6 Member

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    Sonuvagun I think you have it. I guess thats why I had leftover pins (which I thought were meant for use on drive cups of the trans)...yet another tear down of the trans coming but I bet thats the reason why.

    If thats not it, Ill just try using the extremes, like 4 full turns out and adjusting half turn at a time. But I'm confident its those missing pins (since I replaced very few parts, but the gear was one of them because it stripped)

    I have the Savage 21 version...just the thin metal plate.

    Thanks again!
     
  6. olds97_lss

    olds97_lss Well-Known Member

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    Sucks to have to tear it all apart for that. Hope that's what it is and it's not just the adjustment screw.

    As long as you don't have a really high output engine, it should be fine. Mine was fine with 2 pins using the old OS21RG I had in mine for a long time. It wasn't until I put an SH28 in it that I had the issue and had to update the gear/2 speed. With 1 pin, I did have it break on me once with the weaker engine. With 2 pins, it lasted until I changed the engine, then it didn't last long.
     
  7. chrisexv6

    chrisexv6 Member

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    I have an STS 28 in it, which is fairly high output, but the 2nd gear has held up for about 4 gallons of fuel through the STS, plus the Dynamite 26 that came with the truck when I bought it (used).

    If I have to take it apart again, Ill just put 2 pins in and be done with it.

    Unless the gear comes from HPI with the pins already installed, they are definitely not there. Now I guess the question is if they are installed on the brand new part, Ill have to Google around and see if I can find out.
     
  8. chrisexv6

    chrisexv6 Member

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    Just want to report back and thank you again, @olds97_lss

    Tore the transmission down last night (I'm getting really good at it so it doesnt take very long anymore) and sure enough...no pins. While it was open I installed both pins (so much for "extra parts") and today I just had to tweak the setting. FYI - on the Savage 21 it looks like 3 turns out from bottomed out is a good start....I probably ended up at 3.5 turns out or so and its just about perfect.

    During the off season Ill be looking for a new trans, or at least the updated case and 2nd gear setup to swap into ours.
     
  9. olds97_lss

    olds97_lss Well-Known Member

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    Glad to hear you got it sorted out!

    I don't usually end up with extra screws, but I have ended up with not enough screws a couple times working on a savage. Once, it was a trans case screw that holds the top of the case on, fairly long, hard to lose. Figured it rolled off/behind my workbench, so I put another in.
    Found it about 5 minutes into running the truck... no more go:
    [​IMG]
    [​IMG]

    Then again with my savage flux a last year when I was doing diff work, found it a couple minutes into the run...
    [​IMG]
    [​IMG]

    I much prefer having extra screws because that means I at least didn't leave it somewhere bad. :)
     
  10. ELWOOD

    ELWOOD Well-Known Member

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    OUCH , I can't unsee that now Olds
     
  11. olds97_lss

    olds97_lss Well-Known Member

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    The diff one freaked me out. Was rolling rolling rolling then a loud crack and it wouldn't move. I was pretty new to the flux at the time.

    With the 3-speed gear getting shelled, there was a nitro engine covering up the noise, so didn't hear it's bones break. lol
     
  12. ELWOOD

    ELWOOD Well-Known Member

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    Yea those "Missing Parts" always come back to bite you in the :argh:SS !
     

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