I have a Moser 9" rear end for my equipped with 3.90 rear gears. I want my speedo to read correctly though. Where can I get a speedo gear for that gear ratio? Who makes custom ones?

 

I don't think you can get speedo gears for that ratio. I have never heard of custom ones either. You could put 3:73 speedo gears in and be pretty close. I think that the 3:73 gears arn't that accurate anyway.. now that i think of it i am not that much help. Interesting question though

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There are places out there that can make a gear box for any possible combination. It's a little aluminum box with small gears inside that bolts to the trans and the cable bolts to it (screws to it). I don't remember who but you tell them what rear gear, tire diameter you have and they'll make it.

 

auto meter sells a lttle black box to calibrate your speedo it has two notches on it that you turn with a screwdriver to set a driven gear count and a drive gear count however that is electronic your vss plugs intto it if you have a cable driven speedo i don't know if they have one for it

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IF they made them you would need a 15:47 or a 14:44 combo. The 15 tooth drive gear is easy, the 47 tooth driven is not. And I doubt a 14:44 combo exists.

The 3.73 combo exists, not because GM installed 3.73s with an automatic (I believe that 3.73s were only available on HO L69s with a 5-speed BTW), but because it is a combination of existing drive and driven gears in late model years.

BUT, you should contact a GM dealer (or auto parts store) and see if such a gear (47 tooth driven gear) is availabe on another variant of their cars.

 

If your tire is is 26" the the 15-45 combination will work, if the tire height is close to 27" then the 15-44 will work. If the tire height is somewhat shorter than 26" then you will have go to a speedometer shop to have it dialed in.
Glad Too Help!!!

 

Glenn, 84 was the only year you can get an L69 with an automatic. 83 and 85-86 the L69 is 5-speed only.

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