TH350 Kickdown sticking?

[dhenderz]

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.

 

[78C10BigTen]

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

 

[Matt69olds]

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.

 

[dhenderz]

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.



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[dhenderz]

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.

 

[Nonstop]

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.

 

[ali_c20]

Get some quality cable. I have no good experience with any of the cheap aftermarket cables (pioneer, atp, autometal direct, dorman, ...)

 

[dhenderz]

Get some quality cable. I have no good experience with any of the cheap aftermarket cables (pioneer, atp, autometal direct, dorman, ...)

Any idea on where to obtain good ones? The only suppliers I've seen is Pioneer and ATP for this truck

 

[80BrownK10]

Any idea on where to obtain good ones? The only suppliers I've seen is Pioneer and ATP for this truck

Didn't someone post a link to a custom maker a few posts up?

 

[ali_c20]

Didn't someone post a link to a custom maker a few posts up?

Found it. But it's only speedo cables.

https://speedometercablesusa.com/cables_and_housing_assembly.html

 

[ali_c20]

Any idea on where to obtain good ones? The only suppliers I've seen is Pioneer and ATP for this truck

I think you have to buy a universal cable and fit it for your needs.
https://www.speedwaymotors.com/shop...-trans-kick-downs~66702-1-225-12-20-467-14235
Call their tech support to get the best solution for your application.

 

[dhenderz]

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.