Question about 1993 Toyota 4Runner
The transmission is controlled by the Transmission Control Unit (TCU).
Throttle position, rpm, and speed are input parameters to the TCU. The TCU has a default set of shift patterns. These shift patterns change over time based on your specific vehicle setup and driving habbits.
The shift patterns are only slightly affected by driving habbits over many driving cycles. But, changing the relationship between the throttle position and the actual speed being reported by the speed sensor can have an immediate effect on shift patterns.
While your speedo may now be correct, the realtionship between rpm and thottle position has not been corrected. That would take a gear change in the differentials.
The TCU can be reset to an inital learn base line. When this is done, the TCU will instantly learn the dynamics of your setup.
Any shop with an advanced ODB scan tool can reset the the TCU. The dealer or a transmission shop would be preferable.
You really should change your differential gears as opposed to resetting the TCU
This information was posted by ftgiles here
Posted on Jan 06, 2009
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Posted on Jan 02, 2017
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