My car will randomly shift into 1st gear while
driving down the highway.. I can disconnect the
battery and reconnect and it will clear check
engine light and start shifting normal again. But it
will at any random time be minutes or days
later..shift back into first while driving down
If this is a automatic its probley a faulty shift modual. most tranys have an alectronic box that replaces the linkage cable these days and thats what controls the shifting. I would get it up and check the wiring harness for damage and the plug for corrosion. Does it tend to slip into first when you hit rougher roads? or does it do it on smoth ones as well?