I was just curious if anyone here has calibeted their speedo/odo after a gear swap and/or tire change? If so, how?

I used the Superlift TruSpeed on my truck and I really liked the ease of install, not to mention unlimited calibrations.

Would this work on a 4JG2/UCS69/Isuzu. I see Superlift's application page, but no Isuzu. However, it can't be too far off from GMs wiring/computer system...?

I know many might not think the speedo being off as a big deal. But here in Japan that is actually one of the tests that is run for inspection during JCI time. I don't want to get pinged. Any thoughts on speedo calibration?

I should get under my truck and check, but while I'm here, is there an external VSS/VSSB? Is the speedo/odo run off the same signal to the ECM from a speed sensor?