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Old 06-25-2012, 09:03 PM
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Changing shift points in a GM 200R4 OD transmission

When you upgrade to a 200R4 OD transmission to get the benefits of the 0.67 overdrive, it is rare that the automatic shifting sequence occurs at the proper speed. Most likely you have lower rear end gears and a cam so you want the shifts to occur at a higher RPM but the donor tranny is likely set up for a grocery getter and results in 1-2, 2-3 shifts way too slow for your setup. Thus you are stuck with manual shifting which is fun but there are times you want to set it in drive and run it automatically.

A lot of people suggest changing the shift points by adjusting the throttle cable. DON'T DO THAT! That cable needs to be set properly and left alone. It is the governor that sets the shift timing and you have to modify it.

Here is how we did it. Basically we cut down the weights on the governor which is the proper method.

We ended with perfect shift points for the street; ~2000rpm @ 1-2 and 3000rpm @ 2-3. We havent tried it yet but I assume at WOT the shiftw will rise accordingly to higher in the power band.
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