There are two. One very small only a couple of drops and a larger one at the place where the drive shave exits the rear of the transmission. I do not have a center support on the fire truck as it has a three part drive shaft. I think the front one is the rear main seal but every "old guy" I've spoken with around the firehouse tells me: "they leaked in 1951 and don't worry about it." It is the larger leak at the rear of the transmission that really concerns me as it seems to leak a lot. I do not like small puddles...
