Hey guys, I need to get my speedometer working for my bird. Its a 90 with a T-5 and a rear end re-geared to 3.42 with the stock 245/50R16 tires.

I can't find the plastic speedometer gears, does anyone have them? Or is there like a conversion kit to get the speedometer working accurately?

Thanks,
Matt

 

Check ebay, if your looking for the 41t gear, I had good luck calling local tranny guys, cause nobody's making them.

 

What do you have now?
What all are you missing?

 

I have a blue, 7 tooth drive gear, which I'm not sure is correct. I have a white, 18 tooth driven gear, which would be perfect for a 3.23 ratio, but will be about 5mph off at 60 with my 3.42s. I need a white, 19 tooth driven gear and I'd be all set.

Transmission is out of a 3.08 ratio car, so I believe it has the 9 tooth drive gear. Not sure about the driven gear.

 

And that all should have been in your first post.

Use a sharpie marker; write on the gear in the trans., and count to see if you have a 9. If you do, remove the tailhousing and under the offset lever the shifter seats into are a ball and spring; don't lose those.

I'm used to a purple 7 tooth; but color is not a solid reference. Measure the 7 with a caliper and if it's the same o.d. as the 9 (give or take 0.020") swap it onto the trans. mainshaft and reassemble.

The 18 tooth gear will work but will probably make the speedo fast. A 20 might be preferable. Whether the 88 VSS is correct for a 90, I don't recall. If not, scour the classifieds and eBay.

 

When I made the first post I hadn't found any of the other gears yet, a local transmission shop let me pick thru their junk pile. I appreciate everyone's help, but I'm basically in the same boat I was before, lol. Just a pile of parts that I hope will work. I'm still waiting on the rear end and my new combo valve to come it, then I'll take the car off the road for a little while & tear it all apart.

 

3.42 will take either a 19- or 20-tooth driven gear, based on actual measured radius, NOT the "trade" size of 245 blah blah blah. With those little bitty stock tires in the size they are these days (NOT the same size as they were in 198x) you'll probably come out closer with the 20.

Remember, the steps are around 5% each; it's not like you're going to be able to get very "exact". Don't waste a bunch of time outsmarting yourself over "calculators" and "what the factory used" and all that. Instead, just get it as close as you're going to be able to get it, and accept that it's not going to necessarily be real "exact" because the increments are so big.

 

Well unless I stumble across a 19 or 20 tooth gear before the rear comes back from the shop its going together with the 18 tooth and I'll see how close/far it is, lol. Not like these gears grow on trees, which was really the point of this thread, to see if anybody knew where to find em, lol. I've tried eBay, junkyards, GM, trans shops and they just don't exist anymore, lol

 

I have a 19 tooth (p/n 3987919) White = 3.42 in my car now. I will trade you it if you can find a 20 tooth (p/n 3987920) Blue = 3.45 for me.