I was thinking today, if it was leaking behind the belt pully on the transmission, it would be leaking behind that pully, not onto the rear of the primary. I am losing transmission oil so my question is. Ruling out the seal behind the pully on the transmission, what other way is there for transmission fluid to leak out onto the back of the primary? This is a 5 speed transmission.

 

Oil like water seeks the lowest point. The primary is lower than the pulley. What you have is a classic main shaft leak. Don't over think this, just fix it.

 

Any special tools to get the pully off?

 

A socking great tube socket to undo the nut and some way of locking the tranny...I usually take the selector forks out and lock the tranny by selecting 2 gears at once.

 

So once I undo the nut on the drive belt pully it slides off?

 

Spanners lives in the Southern Hemisphere, so sees things differently to everyone else! You also need to remove the entire primary drive, plus inner casing. Frankly it's the sort of job I would take to a Spanners.....

 

Usually yes, getting the nut off is the hard part. I usually cut the nut off and fit a new one as the new part is cheaper than the time taken to remove the old one.

It is left hand thread.