A/T - 700R4 Missing Reverse Checkball
BULLETIN NO: 257TRANSMISSION: 4L60/700-R4
SUBJECT: Missing Reverse Checkball
APPLICATION: GM
It is not uncommon to find that the checkball in the reverse brake circuit has fallen out (figure one). The checkball was introduced in 1987. It is not imperative that the checkball (or capsule) be in place. If the checkball has fallen out of the capsule, you can either replace the capsule (GM part number 8663890), leave the checkball out or remove the capsule.
Note
Not all 1987 and later 4L60s use the checkball capsule.