Easy way to fit the check ball of Toyota/Aisin automatic transmission into position

Check ball valves in automatic transmissions allow transmission fluid to flow in one direction. It uses fluid pressure to control the opening and closing. In a closed position, the check ball seals where it sits.

WHERE EXACTLY SHOULD AISIN TRANSMISSION CHECK BALL BE FIXED?

The check ball can sometimes be a pain to fit back into its normal position when the transmission valve body is removed.

During valve body removal of Aisin transmissions, the check ball could easily fall off and where it falls from is sometimes a challenge to technicians. The picture attached serves as an example since the check ball position looks identical in many Aisin transmissions.

Securing the check ball and the check ball spring in place before putting the valve body in place can be challenging especially when the transmission is fitted in the car and not on the workbench.

FOLLOW BELOW STEPS TO PUT THE CHECK BALL AND SPRING IN PLACE EASILY:

  • Wipe the position where the check ball and spring should stay off with a clean dry cloth. This will remove oil that can prevent the petroleum jelly which is going to be applied from sticking with the transmission casing.
  • Use petroleum jelly to hold the check ball in place before putting the valve body. The petroleum jelly should be a thick type as there are some that are quite light.

Then gently put the valve body in place and secure it with its screws.

Care should be taken in order not to mix screws of different dimensions. Some screws are longer than others.

If the check ball is not secured in the correct position, the transmission will not function well.

Note that it is not only AISIN transmissions that use check ball. This article serves as an illustration of an easy way to fix the checkball which is sometimes not very easy to fit in place.