How do you tell if your transmission was damaged in an accident?

Earlier this year, we were asked to examine a vehicle that was involved in a two vehicle accident and make a determination of the condition of the transmission pre-impact. The vehicle that was involved was a 2008 Buick Enclave that had already been repaired by the owner’s insurance carrier. The issue of the condition of the transmission arose after the vehicle had been returned to the owner and the owner subsequently drove the vehicle an additional 3100 miles. The transmission became noisy and then failed to move the vehicle after being placed in “Drive”. While investigating this incident, it was learned that the vehicle had been taken to a Valvoline Instant Oil Change Center where all the fluid levels were checked and documented. The transmission was found to have been “full” shortly before the accident occurred.   It was further learned from the body shop that repaired the vehicle that no transmission fluid came out of the transmission fluid cooler lines when the cooler and radiator were removed for replacement – the fluid level was already “low” when the vehicle arrived at the shop. Furthermore, after the new cooler and radiator were installed, no transmission fluid was added before the vehicle was returned to the owner. The vehicle left the body shop with the transmission at some fluid level below “full”. Normal wear and tear on a transmission is a very gradual process. The speed of the wear process is increased when the transmission is forced to operate without lubrication, which is the purpose of the transmission fluid. However, when there is documentation of the fluid level, the process of determining transmission condition becomes a lot easier. The damage to the transmission most likely occurred as a result the accident. The transmission was leaking fluid after the vehicle was returned to the owner.