CT5590 - A new front pump seal and rear seal for Turbo Hydramatic 400 transmission 1965-up. This kit fits the most common TH400 transmissions. The front pump seal fits all models of the TH400. The rear seal has an OD of 2.702 to 2.708. Please compare to your existing seal as rear seal sizes will vary on the TH400. This is known as the large rear seal. Please contact us if your seal is smaller. The front pump seal measures 2.765 to 2.770 inches. New and unused.