TH350 won't kick down (no passing gear) - The 1947 - Present Chevrolet & GMC Truck Message Board Network

RainFade · 12-30-2004, 12:15 PM

My 71 had a th350 tranny that seems to work GREAT, no slipping, upshifts great but won't kick down.

I've done the lift the plastic tab, open to WOT push the tab back in thing to no avail, even tried it at 3/4 throttle no joy.

I assume it's connected inside the tranny as it retracts, or is this a bad assumption ?

Beyond pulling it out of the tranny to make sure it's connected to the what I understand is a springy wire sort of thing are there any other things I can try ?

This truck is new to me and supposedly had tranny work done to it in the past, could they have done something to the valve body and now it's just manual and the kickdown isn't going to work, are there common things that can go wrong in a 350 to keep it from kicking down yet the tranny otherwise seems fine ?

T.I.A.

Brian

CHEVY & GMC FOREVER · 12-30-2004, 08:15 PM

does the tranny kick down at all?

CHEVY & GMC FOREVER · 12-30-2004, 08:17 PM

If the tranny is not Kicking down at all it could be 2-3 valves stuck, detent valve and linkage sticking or broken......

784X4GUY · 12-30-2004, 08:26 PM

If it is springing back that probably means that everything is good at least with the linkage where it connects at the tranny. Could be something more complex than just that though. Good luck with it...Later Mike

Longhorn Man · 12-30-2004, 09:38 PM

What kind of carb are we dealing with here...can you get a pic of the throttle?
I'm wondering if the carb is pulling the cable enough.

Try this, disconnect the kickdown cable from the carb. Pull the cable out as far as you can. Now secure it in that position....a zip tie, or maybe some vice grips...what ever. Now drive it down the road. if it shifts into second like normal, then there is a problem in the cable or tranny. If it stays in first untill 35 MPH or so (5500 RPM), then there is a problem with the adjustment or the carb is not pulling the cable enough

RainFade · 12-31-2004, 10:48 AM

It did it with the quadrajunk the previous owner had on it, and does it with my 1406 as well.

It does not kick down at all, making me fearful a tranny R&R is in my future... but it works GREAT otherwise

Oh well just some of the joys of a 30+ year old truck that is new to me.

Thanks guys I really appreciate the feedback this chevy stuff is awfully new to me but I am learning.... necessity being the mother err something or other

12-30-2004, 12:15 PM	#1
RainFade Registered User Join Date: Nov 2004 Location: Central Ohio Posts: 215	TH350 won't kick down (no passing gear) My 71 had a th350 tranny that seems to work GREAT, no slipping, upshifts great but won't kick down. I've done the lift the plastic tab, open to WOT push the tab back in thing to no avail, even tried it at 3/4 throttle no joy. I assume it's connected inside the tranny as it retracts, or is this a bad assumption ? Beyond pulling it out of the tranny to make sure it's connected to the what I understand is a springy wire sort of thing are there any other things I can try ? This truck is new to me and supposedly had tranny work done to it in the past, could they have done something to the valve body and now it's just manual and the kickdown isn't going to work, are there common things that can go wrong in a 350 to keep it from kicking down yet the tranny otherwise seems fine ? T.I.A. Brian __________________ 71 K20 350/350/205, dealer air, 4" lift, Flowtech,Edel 1406 on 2101, procomp HEI,4.10's, 33x12.50x16.5 BFG MT's on slots. 4 wheel disc brakes. My lame K20 page My lame Eaton disc brake page

12-30-2004, 08:26 PM	#4
784X4GUY Did someone say MUD? Join Date: Aug 2003 Location: Pullman,WA Posts: 1,089	If it is springing back that probably means that everything is good at least with the linkage where it connects at the tranny. Could be something more complex than just that though. Good luck with it...Later Mike __________________ Im in the market guys...so keep ya eyes peeled -------------------- Mini trucks are for guys who cant get it up!

12-31-2004, 10:48 AM	#6
RainFade Registered User Join Date: Nov 2004 Location: Central Ohio Posts: 215	It did it with the quadrajunk the previous owner had on it, and does it with my 1406 as well. It does not kick down at all, making me fearful a tranny R&R is in my future... but it works GREAT otherwise Oh well just some of the joys of a 30+ year old truck that is new to me. Thanks guys I really appreciate the feedback this chevy stuff is awfully new to me but I am learning.... necessity being the mother err something or other __________________ 71 K20 350/350/205, dealer air, 4" lift, Flowtech,Edel 1406 on 2101, procomp HEI,4.10's, 33x12.50x16.5 BFG MT's on slots. 4 wheel disc brakes. My lame K20 page My lame Eaton disc brake page

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12-30-2004, 08:15 PM	#2
CHEVY & GMC FOREVER Registered User Join Date: Nov 2004 Location: New Lenox,IL Posts: 306	does the tranny kick down at all?

12-30-2004, 08:17 PM	#3
CHEVY & GMC FOREVER Registered User Join Date: Nov 2004 Location: New Lenox,IL Posts: 306	If the tranny is not Kicking down at all it could be 2-3 valves stuck, detent valve and linkage sticking or broken......

12-30-2004, 09:38 PM	#5
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	What kind of carb are we dealing with here...can you get a pic of the throttle? I'm wondering if the carb is pulling the cable enough. Try this, disconnect the kickdown cable from the carb. Pull the cable out as far as you can. Now secure it in that position....a zip tie, or maybe some vice grips...what ever. Now drive it down the road. if it shifts into second like normal, then there is a problem in the cable or tranny. If it stays in first untill 35 MPH or so (5500 RPM), then there is a problem with the adjustment or the carb is not pulling the cable enough



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