Deal with the problem in stages. Get estimates from different companies ( not the cosmetic type contractors) and/or engineers to help determine the actual cause and soil type you are dealing with. If its regular ole clay the last thing you want is to add water which will compound the side load by 10 fold. There are several forces and reactions on foundations. One being the expansion and contraction of the house on the top of the foundation wall pushing, pulling and flexing the top if it can not slide on the plate. Another is the side load of the earth surrounding it, view that as a heavy force leaning on a tree, the wall will bend if its not strong enough and darn few regular foundations are these days. Another is soil stability beneath the footers, be it soft soil, seasonal conditions like quicksand, or as a slow land slide on the side of hills. One other to consider in this type of case is if the garage gets below freezing temp inside, if so you now have the house footer and supporting soil subject to freezing and heaving. I致e used all types of methods for foundation work , from death men anchors to floating the whole house unit above a quicksand pocket, but no one method works for all foundations. The only tuck pointing compounds strong enough to resist cracking are epoxies and then the wall just cracks along side the patch if you don奏 fix the actual cause. In a few rare cases one can use a polyurethane joint compound but those are strictly for watertight cosmetics. So do your homework first and figure out the reason for the shift. Check straightness of walls, comparisons of elevations of wall tops, outside drainage, soil type and how it reacts etc and get advice. With that info you can then decide on a method that fixes it for a few years or once and for all.
