.....hiya, fluid coming from the brake booster is very dangerous. Does the pedal feel hard when applying the brakes ? If so it could be the rear seal on the brake master cylinder is leaking into the booster chamber. Removing the vacuum hose and putting a thin stick into the hole and see if there is any quantity of fluid showing. Does the brake fluid level drop over a short period of time ? The transmission is not connected to the brakes unless it has a vacuum assist from a common vacuum reservoir.