russell-t

63 Olds 215 4bbl.Does anyone out there( maybe Joe P.),know what this

linkage spring does? Mine is missing.It appears to somehow control the

transmission downshift function,but how? I've spent about an hour opening

and closing the linkage on my 4bbl trying to figure what this spring does.

The picture is the linkage on a 62 Cutlass 215 4bbl. owned by my son.

This spring is enormous,and must control transmission function in some way.

It it a tension or a compression spring? Can anyone tell me why this is here?

72 cutlass455

Almost looks like a kick down rod that was used in my ford. If the the rod goes to the tranny and it is a auto would cause the tranny to down shift if needed to pass and such.

joe_padavano

Well, since you asked...

It's part of the throttle valve linkage. The RotoHydramatic 5 doesn't use a kickdown, it uses a throttle valve (like a 200-4R or 700R4) to modulate line pressure in the trans based on throttle position. The TV rod also acts as the kickdown link. The RH5 has a "feature" that you could fully open the throttle without activating the kickdown if you wanted to on the freeway, then by pressing slightly further on the throttle this bellcrank would activate the kickdown.

Of course, I eliminated this when I went to the E-brock carb on mine and had to fabricate my own throttle and TV linkages.

russell-t

Joe, Thanks for the reply. Does this spring hold back the downshift

process until the pedal is completely depressed? As my car is now, it will

downshift to 2nd at speeds under 35-40 mph. At speeds above it I have to

push the pedal to the floor and even then I can only feel the 4bbl open up.

Downshift linkage must not be properly adjusted or I would get passing

gear when I push the pedal to the metal. Will be checking that out.

russell-t

After some searching at swap meets and parts stores I found a spring

that closely matches the one in the picture. Took about an hour to install

and readjust the linkage to the spring. My opinion is that this spring holds

the transmission linkage up tightly in a firm position. Without it my trans

shift points would vary constantly with every stop and start. This linkage

has a slot in it which is not visible in the picture, but allows movement for

passing gear when the pedal is pushed to the floor.

The TV rod is attached to this slotted portion of the linkage, and will

move into infinitely variable positions without this spring attached to it.

The result is with every stop and start,you end up with a different TV

adjustment. This changes the 1-2 shift every time you start out from a

stop. I would like to have back the hour or two of my life I've spent

adjusting and readjusting the TV rod to get the right 1-2 shift point.

The answer to the original question is....the spring holds the linkage

together to keep shift points consistant.