Speedo recalibration possible?

Tiny
TRIUMPHNUT
  • MEMBER
  • CHEVROLET SILVERADO
I swapped the rearends out of a 92 sierra 5.7, 5spd stick with a 3.08 ring and pinion, and a 93 sierra 4.3, 5 spd stick with a 3.43 ring and pinion. Now the speedo's are off a bit, one reads high and the other is low. I can't believe the lack of info on how to get the speedo recalibated. Local dealers can't do it and don't know where to send me to have it done. The transmissiions both have elecronic sensors/counters on them and therefore can't be adjusted the way the old style cable drives used to using a swappable nylon drive gear. I'm told the cluster has to be re programmed but the dealers only have the ability to flash the original factory data from the serial number build info back into it. I see a recalibration device is available thru Summit Racing but the $300 price tag is not cost effective. Someone has to be able to reprogram this thing! People are looking at me like I've got 3 heads for doing what I did, as if they'd never heard of doing this! Help!
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Saturday, March 3rd, 2007 AT 2:09 PM

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Tiny
CHEVYII
  • MEMBER
Hi
I worked and still work for gm and have done the reprogram many times, its very easy takes about 10-15 minutes, my guess is that they dont know how to do it or just wont do it, soory your having tough luck, someone can do it for you, if you were in my state I would be glad to do it for free

jim
if you are happy with the info please leave feedback we all here do this for free feedback is a way of saying thank you for the help
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Saturday, March 3rd, 2007 AT 2:18 PM
Tiny
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Hi Jim,
Thanks for that advice. Can you tell me what specifically needs done? That way maybe the dealer can get a clue and help me out. I've been researching on google and have found some info. I can't tell if my trucks have the DRAC that needs physically replaced or some other plug in module that needs to have pins configured differently. Or can it be reprogrammed thru the diagnostic port? My dealer says he cannot change the info, only reload original specs.

It seems I have learned that an external signal recalibrator will screw up the ABS and the cruise control as the speed sensor feeds these other two systems as well, so I guess that's not a last resort option either.

Thanks, Jim.
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Saturday, March 3rd, 2007 AT 5:49 PM
Tiny
CHEVYII
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Hey guy, I missed what year it was but it still doesnt matter, the drac is programmable, I remember a bulletin about customers changing gear ratio at the time of purchase and you could have gm send one out or reprogram at the shop, it can be done, and it is done through the diag port, I think because its obd I they may not want to mess with it, pretty simple though
good luck and let me know what happens
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Saturday, March 3rd, 2007 AT 6:40 PM

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