TCS Trans Switch Operation / Adjustment?

[Tim S.]

I am working on my 70 LS5 car in preparation for the upcoming Regional. The TCS operates properly in 3rd gear, but not in 4th. The switch on the trans cover is open in 3rd gear, and has continuity in neutural and 4th. Obviously, when the switch is open the vacuum valve opens.

That all having been said, is there an adjustment to this switch? I don't recall such a thing nor do I see it. The switch is cetainly working. The only other thing could be an issue on the shift fork mechanism inside the side cover. I'd find that a little suprising as the car has not been apart (that I am aware of) as it is an 8900 mile car. I'd suspect it was like this from day 1

Your thoughts?

Thanks,
Tim

[Gary B.]

Re: TCS Trans Switch Operation / Adjustment?

The shifting fork has 2-45-degree flats ground on it. If the transmission has been apart, it's common to install the the shift fork 180-degrees off. This will cause it to work in one gear, but not the other.

If you pull the switch out of the side cover, look into the hole and "hope" you see both flats when you shift from 3rd to 4th.

If you do, replace the switch with a new one, that has a steel ball. They don't wears as much.

Gary B

[Mark E.]

Re: TCS Trans Switch Operation / Adjustment?

Vacuum should be blocked in gears 1-3, and available in 4th. What's your car doing?

[Tim S.]

Re: TCS Trans Switch Operation / Adjustment?

Thanks Gary. Makes perfect sense. I appreciate the time and consideration!

Tim

[Tim S.]

Re: TCS Trans Switch Operation / Adjustment?

Vacuum should be blocked in gears 1-3, and available in 4th. What's your car doing?

I get the vacuum advance in 3rd gear, but not in 4th. As I read when I started to investigate, I should have it in both 3rd and 4th gear.