My Corolla gearbox jerks
Hello Paul, when I put myCorolla S 2005 in reverse, it sometimes goes on smoothly or the car will jerk as if it is on hand brake. My mechanic has tried to service the gear box to no avail. What should be my next course of action? Bitrus
Hello Bitrus, I presume your mechanic has checked the gearbox mounting (suspension) as it can cause a slight jerk when you shift. If the jerking is severe, have the automatic transmission carefully diagnosed to rule out transmission fluid (ATF) restriction, usually caused by a dirty or restricted ATF filter in the gearbox, even after you change just the ATF.
A computer diagnosis would be a useful way to examine the automatic gearbox electrics, particularly the valve body solenoids, which control and allow flow of ATF to particular gear bundles. The automatic gearbox valve body and solenoids will get damaged when you fail to renew the ATF fluid and it starts to overheat or becomes very dirty with sludge, which damages the valve body and solenoids.
When the valve block or solenoids are damaged, they will restrict ATF flow, which can cause a jerk when you demand performance by accelerating. A faulty transmission pump will also cause that sort of jerk, even after you service the gearbox.
