It is often both difficult and time consuming to accurately air check for internal 3-4 drum leakage in vehicles with F4A-EL or G4A-EL transmissions. If the drum leaks, the proper amount of fluid pressure is not applying the clutch piston, resulting in burned clutches, slips or no 2-3 shifts. Currently the only way to air check this drum is while it is in the case. This leakage can often be the result of a poor or cracked weld at the back of the 3-4 drum or worn seals. The weld and seals assist in separating the apply pressure fluid passage from the lubrication circuit. Thus if the weld and seals are not sound, cross-leakage occurs. Sonnax offers a drum test tool for both the F4A-EL and G4A-EL transmissions that will aid in quickly determining if the 3-4 drum leaks.