i guess a lot of people will find this gearbox stuff boring..i know one of the hardest parts i found was trying to read one full paragraph of the Bently manual without falling asleep,so i'll try and hurry it up.
was fairly happy with the pre-load,so next borrowed a dial-test-indicator from Ray,and tryed to measure the backlash,which is the play between the ring gear,and the pinion gear..
this piece of angle bolted to the back of the gearbox locks the pinion shaft(i think its called)so the pinion gear cant move,and the play between the pinion gear and ring gear can be measured at the output shaft..
after a lot of messing around,i have the backlash down to .012". i believe it should be between .006" and .010" ideally.this is as close as i can get it with the shim i have at the moment.i need to find out if .012" is ok or not,but it wont be driving down the road for a while yet,so theres no panic.