rear end gears

Is it true that if you take the gears out of a GM 10 bolt rear, it is really hard to install them? Smeone told me you need to shim them up or something and it's incredibly hard to align everything up. The most i've ever taken out of an s10 rear is the axles. Any info will help.

all rearends needs shims and what not in way shape or form. it is not for the novice.

cookie

for a first timer i wouldn't do i have an 04 chevy and i put in 3:73 with an eaton locker and i had to have a friend come over and finsh up with the back lash...if your only doing gears becarful with the two littel spider gears in the knew cheveyys 00-06