Well today i got 3 new stock spur gears because my first one stripped.
I fitted it, adjusted the motor from side to side to get the mesh correct but then i noticed a problem.
The spur gear is not in-line with the clutch bell. Its hard to explain so i made this:



Where the red is in the drawing is where the clutch bell is in contact with the spur gear and when i push the car backwards it grinds.
Either the clutch bell is too far forward or the spur gear is too far back. I tried with all 3 spur gears and its still the same. After looking at the old stripped spur i realised that the slipper pad that was in that was a lot thinner than the new pads that came with the new spurs......other than that they are exactly the same. Why would the newer pads be thicker which pushes the spur gear out more therefore making the spur and clutch bell contact?????
I sanded the side of the spur gear (not the teeth obviously) until it was not so bad but still as you can see in the drawing only a proportion of the spur gear has meshed with the clutch bell because they are still quite out of line with eachother meaing there will be less contact which means it is more likely to strip again. I hope you understand what i mean.

Is the thickness of the pads the problem.....or is there something else that i have missed???
How could i fix this problem?

Thanks, Daniel