How To Replace Shimano Shifter. Take care for the little bit of plastic pictured right that guides the cable around the bend. Operate the shifter to set it to the top rear low front position.

The coverplate can take a bit of fiddling to get it to click into place. Consider swapping out your old shifter cables. A small lever just behind the brake lever shifts the chain onto a smaller cog while the whole brake lever can be pushed to the side to shift to a larger cog.
Remove the front plastic screw and remove the plastic cable holder.
Here is the diagram. XTR SAINT DEORE XT Components for replacement with I-spec are not available for SLX and DEORE. So remove that as well. While turning the front chainwheel operate the lever to shift to the lowest gear.

