* The specific transmission: A TH350, 700R4, 4L60E, or other transmissions used behind a 350 Chevy small-block all have different bolt patterns and numbers of bolts.
* The bellhousing: The bellhousing connecting the transmission to the engine also has bolts, and the number varies slightly between different bellhousings.
* Other components: The number will increase if you count bolts for the oil pan, tailshaft housing, etc.
To get an accurate answer, you need to specify the exact transmission model and what you consider to be "on" the transmission (just the case itself, or including the bellhousing and other components).
