VSS speed problem, need HELP!

[blazindorito]

I have a 400 / 205 combo in my truck and I am ready to drive this beast. I have one draw back how do I hook a VSS sensor to a truck that is carburated? Can it be done? I need it to shift gears on the tranny using the carburetor? What to do? Thanks and all your help is appreciated.

 

[dyeager535]

I don't understand what you are trying to do.

A TH400 doesn't use VSS to shift, and a carburetor could care less, so....

Only reason to have VSS in your case I can think of is a '90-91 electronic speedo, or you want cruise to work.

 

[blazindorito]

I took it to the guy in the transmission shop and told me he couldn't connect the kickdown cable because it needed to have a vss sensor. I have the stock gauges from the 83 blazer. What do I need to find out to connect to have the tranny change the gears?

 

[dyeager535]

There is no kickdown cable on a TH400.

It uses a kickdown solenoid, the way GM did it was a switch on the gas pedal. When you hit the switch by depressing the gas pedal, it downshifted. Simple. *Not* required for the transmission to work, it doesn't hurt anything to not be connected, it simply won't automatically downshift for passing, etc.

You could wire in a toggle switch or something, but kind of pointless for a kickdown if you ask me. The switch setup shouldn't be that hard to find.

 

[Thunder]

I would avoid that tranny shop. Stay Away.
No Vss needed to shift a TH400. nothing electric there except what Dorian said about the kickdown solenoid.
If your tranny is not shifting. You prolly need to hook up or check the the vacuum modulator. Therer should be a vacuum line going from the intake manifold to a small can looking thing on the side of the tranny. The trans wont shift properly unless the modulator is hooked up to manifold vacuum.
Check that the line is hooked up or if there are leaks in the line.

 

[broncoman6524]

I would avoid that tranny shop. Stay Away.
No Vss needed to shift a TH400. nothing electric there except what Dorian said about the kickdown solenoid.
If your tranny is not shifting. You prolly need to hook up or check the the vacuum modulator. Therer should be a vacuum line going from the intake manifold to a small can looking thing on the side of the tranny. The trans wont shift properly unless the modulator is hooked up to manifold vacuum.
Check that the line is hooked up or if there are leaks in the line.

x2


as for the kickdown there is a B&m kit that you can use ( i did and am pleased)
OR i know that brothers sells a replacemetn harness for it,but im not sure if it includes the actuall swith or not. really is just a slider switch, 1constant power, ground, and another wire the the tab ont he tranny.