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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: GUITAR1989 on December 09, 2010, 08:49:27 pm
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Hey guys my brother and I measured my driveshaft today and went to the driveline shop to get one built for my truck :) When we had my tail housing off I was looking at the speedo gear and saw that I could spin it freely without my output shaft spinning at all or even making contact with it. Im guessing that gear should make contact with my output shaft "wich is a TH400 output shaft btw". My transmissions a TH375 out of a 74' chevy wagon. My question is...How do I determine the right speedo gear for my truck? Im thinking I need to know my gear ratio..wich i dont :( If you can tell by tire size my tires are p275/60R15
any helps much appreciated guys :)
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Tire size has nothing to do with the gears. You have to pull the diff cover off and roll the ring gear over and get the number off and divide.