910 5 speed gearbox advice (Read 150 times)

[nisfan]

Hi im needing a bit of advice regarding my 910 gearbox, after standing for 20 years the car was driven 200 miles before the gearbox oil was changed .It was replaced by castrol GL4 and filled to the bottom of the plughole @ 25700 miles.

Its now currently on 27k and is now hard to select 1st and 2nd when cold, whines a little bit in 2nd and is now leaking really bad out of i suspect the output shaft as their is oil all over where the prop and gearbox join, which has then sprayed everywhere.

So, whats the best plan of action? Change the box or replace the oil seal and it should last for many more miles? I know later nissan boxes were the weakest link, is this the case with earlier nissan'datsuns?