My speedometer and transmission acting funny


Asked by Sep 24, 2016 at 09:59 PM about the 2002 GMC Safari

Question type: Maintenance & Repair

OK here is my problem when I drive my 2002 GM
safari van my speedometer would just go up an
down an the transmission starts to act funny so I
can't drive the freeway but when I take the streets
it's semi okay someone told me change the speed
sensor on the transmission so I did and still having
the same issues can anyone help me PLEASE IM

2 Answers


Did you reset the computer after the new part was installed? That needs to be done after parts are replaced so the computer can reset it's programming for a properly functioning part. If after the reset you still have the problem then the system is going to have to be live data scanned so the tech can see what is actually going on with the sensors and the ECM response to those readings. It is possible something else could be out of specs.


if your torque converter is going this can happen its often called sliping. Also if the trany gears are worn they can slip while they are in motion.

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