Ratio Adapter Drive Key

[MylesNT]

I feel like I've talked about this here before, but I guess not. My speedometer didn't work when I started on the truck. It turned out to be the drive key for the ratio adapter had snapped where it transitions to the square shape of speedo cable. I ordered another one a few years ago. It didn't fit. So I ordered another one from a different seller. It doesn't fit either. Apparently, the only keys I can find are for aftermarket ratio adapters.

My ratio adapter is this one:

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The drive key in question looks like this:

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This is the fitment problem:

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I searched and found a few links that would get me a whole new adapter. That's like $150. If I have to get one, I will, but not just yet. The phone GPS speedo works fine for now.

I've Googled and eBayed a ton and came up empty handed. I tried to grind the other one I bought down to fit. Does anybody have any info on where I might find one? Do you have one in a drawer you would want to sell? I can dig up my calipers to see how big this one is so we know what won't fit. There's not many junk yards around, and the ones that are don't have any squarebodys to speak of.

Any info is appreciated.

 

[bucket]

The ratio adapters I have had were a rectangular box shape and used different guts than that.

Have you tried hooking up the speedo cable without it, to see how far off the speedo is?

 

[MylesNT]

I'm worried that the little key will prove impossible to find and require me to update it to one like you're talking about.

I'm running the cable plugged straight in right now. It shows between 40-45 at 65. I can adapt to that, but I'd like for the odometer to be a little closer for the engine break in, which is why I've been using my phone.

 

[idahovette]

Is there a chance part of the old key is broken off inside, not letting it bottom out?

 

[dajn37]

Is there a chance part of the old key is broken off inside, not letting it bottom out?

No

 

[MylesNT]

Is there a chance part of the old key is broken off inside, not letting it bottom out?

No

Yeah. Unfortunately, it just won’t fit.

 

[dajn37]

Are you sure?

 

[MylesNT]

Are you sure?

Yes sir. I’m pretty sure.

 

[Craig 85]

I took this Stewart Warner adapter out of my last truck (203 NP case) when I did the axle swap/gear change 5-6 years ago. I don't need it for my K30.

I cleaned it off and looks like the same ratio as your's. Here's the measurements of the removable shaft.

1.244" overall length
0.450" bottom of shoulder to tip inside adapter
0.170" diameter shaft

If it will work let me know. I can send you the whole thing.

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[MylesNT]

My man! PM on the way.

 

[85 CA SIERRA 1500]

I took this Stewart Warner adapter out of my last truck (203 NP case) when I did the axle swap/gear change 5-6 years ago. I don't need it for my K30.

I cleaned it off and looks like the same ratio as your's. Here's the measurements of the removable shaft.

1.244" overall length
0.450" bottom of shoulder to tip inside adapter
0.170" diameter shaft

If it will work let me know. I can send you the whole thing.
From one '85 to another,,,,,,Craig, thankyou for reminding me that there are still good people in the world. I am certain that the good karma you put out will come back tenfold

 

[CSFJ]

Had to replace one of those on a '79 I had back in high school. At the time ('93-'94ish) there was still a chevy dealer that stocked them in the Flint area. Guess I should've got a handful of them, since they've disappeared completely.