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i have 3.55s and hate them i want the 3.92s , do i need to do anything to the PCM or anything else to make it work or can i just buy the new axle assembly's and replace the 3.55s and roll out?
 

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The PCM will have to be flashed for your gear change to accomodate the speedo. You can do this with a tuner or have it done at a dealer. Otherwise its all bolt up and go.
 

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Shoo Shoo Retarded Flu !!
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The PCM will have to be flashed for your gear change to accomodate the speedo. You can do this with a tuner or have it done at a dealer. Otherwise its all bolt up and go.
This is wrong. The gears can be changed with reprogramming or anything needed. It's when he switches tire diameter that the computer needs to be reflashed. The setting is called pinion factor
 

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How come it can accomodate for gear changes but not tire size change? Seems the same to me, thats weird.
 

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Shoo Shoo Retarded Flu !!
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The reluctor ring, in the rear end, is the same whatever gear ratio you have. The PCM calibrates the speedo by using tire revolutions per mile. it pays no attention to gear ratio. That's why you need to change it. The pinion factor sets that revs per mile paramter in the computer. If you change tire diameters, you need to tell the PCM about that, so it can do the correct "math"
 

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Is that the the ring thats on the ring gear? Or is that for the ABS
 
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