1965 833 4sp. tailshaft seal R&R

Here's what the 65 FSM says:

QUOTE
Rear Oil Seal
Removal

(1) Disconnect the propeller shaft at the transmission flange and secure the shaft to the frame member for working clearance.

(2) Hold the mainshaft with Tool C-3281, then remove the flange nut and washer.

(3) Remove the transmission flange, using Tool C454 if necessary.

(4) Remove the oil seal, using Tool C-748.

Installation

(1) Drive a new seal into the extension housing, using Tool C-3837.

(2) Install the transmission flange, washer and nut. Tighten nut to 175 foot-pounds torque.

(3) Reconnect the propeller shaft and tighten the flange nuts to 30 foot-pounds torque.

UNQUOTE

Guess if you worked at the dealer, you'd know what specialty tools to use.