I recently had an engine replaced on an RX 350 that resulted from a sudden water pump failure. Within a week of picking up the vehicle from the engine replacement repair, I started to have severe transmission problems, which when diagnosised further indicated that the transmission needed to be replaced/rebuilt. When the replacement of the transmission was being made, the transmission shop discovered that the pins connecting the engine to the transmission were missing.

The question: Could have the failure to replace the connecting pins by the shop that replaced the engine caused the failure of the transmission?