TH400 Shifting problems
Thread Starter
Instructor
Joined: Jun 2003
Posts: 130
Likes: 3
From: Halethorpe MD
TH400 Shifting problems
I am having some problems with the TH400 in my 67 Firebird, I know this is not Corvette related but I can't seem to get any answers anywhere else, so I thought I would try here.
My TH400 is shifting early and very soft and won't downshift under heavy throttle. I am going to replace the modulator, but I also have discovered that I do not have a kickdown switch. It is supposed to be mounted to the carbuerator linkage somewhere, but I can't find any diagrams or pictures. I would assume that it is the same setup as a Corvette would have. Does anyone have any idea how to hook one up?
Thanks.
My TH400 is shifting early and very soft and won't downshift under heavy throttle. I am going to replace the modulator, but I also have discovered that I do not have a kickdown switch. It is supposed to be mounted to the carbuerator linkage somewhere, but I can't find any diagrams or pictures. I would assume that it is the same setup as a Corvette would have. Does anyone have any idea how to hook one up?
Thanks.
Drifting
Joined: Mar 2005
Posts: 1,806
Likes: 3
From: Burlington WI
Here is a quote from:
How to Work With and Modify the Turbo Hydra-Matic 400 Transmission
ISBN 0-87938-267-8
I reccomend this book highly!!
"Where is it?
The downshift linkage adjustment is made at the detent or detent/stator switch. Since the 400 was first introduced in 1964, numerous switch types and switch locations have been used.
Most often the switch is located at the carburetor throttle lever, or under the instrument panel, above the accelorator pedal."
My bet is that the detent switch is above the accelorator pedal on your car. Either it has failed, is out of adjustment, or has been disconnected.
ISBN 0-87938-267-8
I reccomend this book highly!!
"Where is it?
The downshift linkage adjustment is made at the detent or detent/stator switch. Since the 400 was first introduced in 1964, numerous switch types and switch locations have been used.
Most often the switch is located at the carburetor throttle lever, or under the instrument panel, above the accelorator pedal."
My bet is that the detent switch is above the accelorator pedal on your car. Either it has failed, is out of adjustment, or has been disconnected.
