1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

TH350 Kickdown sticking?

Discussion in 'Transmission & Transfer Case' started by dhenderz, Nov 28, 2019.

  1. dhenderz

    dhenderz Full Access Member

    Posts:
    114
    Likes Received:
    70
    Joined:
    Nov 30, 2018
    Location:
    Michigan
    First Name:
    Dennis
    Truck Year:
    1977
    Truck Model:
    K10
    Engine Size:
    327
    Hoping someone has some expertise with the TH350. I completely rebuilt the TH350 for the 77 K10. It is reinstalled along with the engine. I replaced the kickdown cable. I have the kickdown cable attached to the throttle body (upgraded to fuel injection). When I manually open the throttle to WOT, the kickdown cable will 'pull' the kickdown wire & activate the valve in the trans. The issue, if it really is an issue, is when I return the throttle to closed, the kickdown mechanism (valve in the trans) is not returning. If I give it a small 'nudge' at the carb end of the cable (push it back in), it will go back to normal position. Is this normal?

    Bear in mind the engine is not running. Also, I have not put any trans fluid in the unit yet - only assembly lube during the rebuild. Would either of these cause this 'sticking' issue? Is there a spring inside that valve that is supposed to pull the cable back when the throttle is closed? Does it require the engine to be running (ie: trans fluid pressure) to pull the cable back?

    I am wondering if I need to pull the pan back off to see what's going on. Or of this is totally normal and to not worry about it.

    Thanks.
     
  2. 78C10BigTen

    78C10BigTen Full Access Member

    Posts:
    6,288
    Likes Received:
    4,214
    Joined:
    Apr 12, 2017
    Location:
    pennsylvannia
    First Name:
    ted
    Truck Year:
    1978
    Truck Model:
    C10 BIG TEN
    Engine Size:
    350
    If i remember correctly theres a small s hook that connects the cable to the slide thing in the trans and i believe there is a spring attatched. Its been awhile since ive had my cable off
     
  3. Matt69olds

    Matt69olds Full Access Member

    Posts:
    509
    Likes Received:
    447
    Joined:
    Jan 8, 2018
    Location:
    Central Indiana
    First Name:
    Matt
    Truck Year:
    81
    Truck Model:
    GMC 1/2 ton
    Engine Size:
    455 Olds
    The plunger in the valve body should snap back when you release the throttle. Assuming you put the valves back in the valve body correctly, you may try loosening all the valve body bolts and retorqueing them, starting from the center and working out in a spiral. The tolerance in a valve body is really tight, it doesn’t take much to tweak the valvebody and cause a valve to bind.
     
    78C10BigTen likes this.
  4. dhenderz

    dhenderz Full Access Member

    Posts:
    114
    Likes Received:
    70
    Joined:
    Nov 30, 2018
    Location:
    Michigan
    First Name:
    Dennis
    Truck Year:
    1977
    Truck Model:
    K10
    Engine Size:
    327
    Thanks. I think I will drop the pan an take a look at the lever and valve. Shouldn't be too much of an issue since there isn't any fluid yet.



    Sent from my iPhone using Tapatalk
     
  5. dhenderz

    dhenderz Full Access Member

    Posts:
    114
    Likes Received:
    70
    Joined:
    Nov 30, 2018
    Location:
    Michigan
    First Name:
    Dennis
    Truck Year:
    1977
    Truck Model:
    K10
    Engine Size:
    327
    Status update. I pulled the kickdown cable out of the trans. The wire going down to the valve works just fine. Lots of spring pressure. Returns immediately to normal position. So no need to pull the pan.

    The issue seems to be within the new kickdown cable itself. If I unhook the cable from the throttle body and straighten the cable out, it works fine - returns immediately when you pull it. But as bend the cable to route it to the throttle body, it starts to bind. The cable is new (ATP brand). I pulled it completely off. The cable doesn't move very easily within the sheathing. Its feels very sticky. I sprayed some lubricant down into the cable sheathing. That seems to have helped. Now after reinstall it does come back to normal position after WOT. Overall I am not really happy with this cable. I am considering trying the Pioneer brand, which is the only other brand Rock Auto carries.
     
  6. Nonstop

    Nonstop Full Access Member

    Posts:
    179
    Likes Received:
    292
    Joined:
    Nov 16, 2014
    Location:
    Ca
    First Name:
    Nick
    Truck Year:
    1985
    Truck Model:
    K2500
    Engine Size:
    454
    I just had the same issue with an off topic car. Cable was sticking. If I am not mistaken, it was a pioneer. Have not replaced it yet, but I am starting to consider aftermarket options since it is possible they are both made by the same company, and there is the sticking issue with both brands.
     
  7. ali_c20

    ali_c20 Full Access Member

    Posts:
    131
    Likes Received:
    111
    Joined:
    Sep 20, 2016
    Location:
    Austria
    First Name:
    Alexander
    Truck Year:
    1974, 1979
    Truck Model:
    C20, K5
    Engine Size:
    350, 350
    Get some quality cable. I have no good experience with any of the cheap aftermarket cables (pioneer, atp, autometal direct, dorman, ...)
     
    Rusty Nail likes this.
  8. dhenderz

    dhenderz Full Access Member

    Posts:
    114
    Likes Received:
    70
    Joined:
    Nov 30, 2018
    Location:
    Michigan
    First Name:
    Dennis
    Truck Year:
    1977
    Truck Model:
    K10
    Engine Size:
    327
    Any idea on where to obtain good ones? The only suppliers I've seen is Pioneer and ATP for this truck
     
  9. 80BrownK10

    80BrownK10 Full Access Member

    Posts:
    134
    Likes Received:
    62
    Joined:
    Oct 22, 2019
    Location:
    Greenwood, SC
    First Name:
    Nate
    Truck Year:
    1980
    Truck Model:
    K10
    Engine Size:
    350
    Didn't someone post a link to a custom maker a few posts up?
     
  10. ali_c20

    ali_c20 Full Access Member

    Posts:
    131
    Likes Received:
    111
    Joined:
    Sep 20, 2016
    Location:
    Austria
    First Name:
    Alexander
    Truck Year:
    1974, 1979
    Truck Model:
    C20, K5
    Engine Size:
    350, 350
  11. ali_c20

    ali_c20 Full Access Member

    Posts:
    131
    Likes Received:
    111
    Joined:
    Sep 20, 2016
    Location:
    Austria
    First Name:
    Alexander
    Truck Year:
    1974, 1979
    Truck Model:
    C20, K5
    Engine Size:
    350, 350
  12. dhenderz

    dhenderz Full Access Member

    Posts:
    114
    Likes Received:
    70
    Joined:
    Nov 30, 2018
    Location:
    Michigan
    First Name:
    Dennis
    Truck Year:
    1977
    Truck Model:
    K10
    Engine Size:
    327
    For what it's worth I did receive and install the Pioneer brand cable. It seems to be a tiny bit better. It does not stick and releases properly after WOT. Will see how long that lasts.
     

Share This Page