A bit more info would be helpful. Assuming TH350, factory or OEM linkage and that this is a new problem.
Have you removed the linkage from the carb to ensure cable or trans connection integrity? I've seen the wire hook at the transmission end break off, leaving the cable to slip back and forth in the sheathing doing nothing more than following throttle linkage movement.
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72 Nova SS, 66 Beaumont Sport Deluxe, 09 Pontiac Solstice GXP Coupe
Thanks, it is attached at the bottom and will kick down for a very short period,I am sure it is a homemade bracket holding it together. Sorry about not supplying more info, it is a 350 with a 350 turbo transmission.
I have adjusted it as much as I can with WOT, but it is a sloppy fit. I just brought the car and am a new GM convert so my knowledge of these is limited.
I've just installed a 350 with TH350 in my 66. I bought a new kick-down cable kit from shiftworks. Easy to install and works great. The kit comes with all the brackets and bits you need to install. It can be ordered directly from shiftworks but, as is possible with most things, I ordered mine from Summit. A little cheaper and their shipping is free to the border if you get your order over a certain dollar total.
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72 Nova SS, 66 Beaumont Sport Deluxe, 09 Pontiac Solstice GXP Coupe
I've just installed a 350 with TH350 in my 66. I bought a new kick-down cable kit from shiftworks. Easy to install and works great. The kit comes with all the brackets and bits you need to install. It can be ordered directly from shiftworks but, as is possible with most things, I ordered mine from Summit. A little cheaper and their shipping is free to the border if you get your order over a certain dollar total.
Lokar Hi-Tech Kickdown Kits KD-2350U
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72 Nova SS, 66 Beaumont Sport Deluxe, 09 Pontiac Solstice GXP Coupe
Another thought, is the vacuum line attached to the transmission. It's been a long time but I recall having an issue with a disconnected vacuum source to the trans.
The vacuum line can be hard to spot. It will be a small metal line, probably bent to follow the contour of the trans, with rubber either end from manifold vacuum to the modulator valve. If the trans is shifting properly I don't think you have a vacuum problem. Kick-down is mechanical and the linkage should be fully extended at full throttle. It's a little tricky to adjust the linkage to full extension without holding back the throttle from full open.
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72 Nova SS, 66 Beaumont Sport Deluxe, 09 Pontiac Solstice GXP Coupe
Installed the new linkage as per the instructions and the trans still wouldn't kickdown. Vacuum line is hooked up and it shifts normally when driving, will only stay in low under full throttle till about 3000 RPM. So I know the linkage is defiantly attached in the transmission for the kickdown? Anyone else have any other ideas?