How To Speedo Gear Correction

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one note for the guy's running 700R4 trans, if you have to change the speedo gears to correct for rear end gear changes, depending on how low or High of a gear set you run, you will need the correct driven gear housing, for driven gears 34 to 39 teeth or for the lower gear sets, 40 to 45 teeth. in GM's infinite wisdom, they stopped making driven speedo gears from 40 and up teeth, so you are left buying an after market gear. I bought the matching housing and gears off Ebay for about $35.00 since I am running 3.73 rear end gears, I needed a Gray, 15 tooth drive gear for the output shaft, and a Black, 40 tooth driven gear for my setup in order to correct my speedo. now, the only thing I wasn't aware of with regards to installing the drive gear on the output shaft of the 700R4, and I'm not sure if the 350 turbo's have this also, but there are two small dimples that the spring clip that holds the drive gear in place on the output shaft, you have to use the forward one of the two holes, if you don't, you'll get what I just encountered.....the gears will not mesh correctly, and they will grind each other's teeth off!!! the whole idea of having the correct housing for the size of the gears for a 700R4 is because they offset the drive hole to accommodate the larger diameter of the gears, but if you don't get the drive gear aligned to the driven gear, you'll be ordering another set of gears just like I did. Hope I save someone a few bucks by not making the same mistake I did.....here's a picture of the gear housing I mentioned...
Ben