Excessive transmission noise in car.

[Reckless Rat]

Have you tried the screwdriver stethoscope method to determine where the noise is coming from? If you get someone else to drive the car, use a big screwdriver and place it against various parts of the car's anatomy and shove the handle end in your ear. I suspect that it's the gearbox as the later synchro ones suffer from thrust wear on the layshaft which would be more evident on "drive" but reduced on over-run when the thrust is in the opposite direction.

[Roger]

Thanks for your reply, I have just received a “stethoscope” from everybody’s favourite online store, unfortunately it is too good and picks up every little noise.
You can’t beat the old screwdriver method. 
I am going to Pembrokeshire classic car show on Sunday so hope to get my friend to listen to all the possible sources on route.

Roger