First off, why are you set on truck brand tools exactly? Do you "have a guy"? For the most part, particularly with respect to small engine and occasional vehicle repair/maintenance, are you really going to see the pay back from buying truck brand tools? I could understand if you were using them professionally, or if you were talking speciality tools where truck brands may be favourable, but for most hand tools it's probably overkill. Make of it what you will, but unless you are making a killing on the side doing small engine work (which I find a reach) save your money and stick to tools that have a decent in store warranty coverage. I can't speak much to the USA equivalent, but in Canada, Mastercraft Maximum and to some extent their basic Mastercraft lines of tools have suited my uses well for years of doing regular maintenance on mowers/trimmers/blowers/etc and the occasional maintenance work on my vehicles.
Now as for small engine repair tools, some things I would recommend to buy include:
- Angle Grinder for doing quick blade sharpening, the trick is that you can do most riding mower blades without even having to take them off, as long as you are careful!
- Bench Grinder for doing blades in a slightly safer and neater fashion.
- Chainsaw sharpener for saw blades, particularly if you can secure a contract with a landscaper or arborist who may want 20 or 30 chains done at a time
- Spark Tester
- mini screwdriver set
- Tire plug kit, some extra valves and a valve tool (one of the four way tools you can pick up for probably 3 or 4 bucks at any big box tool store)
- 1.5" rigid and flexible scrapers for doing deck cleaning
- a set of hand files for doing axe blades, and any finish work on blades for saws etc.
- I'd keep away from 1/2" drive stuff until you really need it, and even then unless you are getting into professional grade machinery, you won't see much stuff that big except on deck spindles for riding mowers.
most hand equipment these days is going with torx bits for a lot of things, so a 3/8" set of torx is really nice to have, grab a set of Gear Wrench combo wrenches, maybe a socket set that covers 1/4 and 3/8 inch stuff and you'll be mostly set as far as basic goes. from there on, it's only tools that make certain jobs easier that you can add on as the need arises.
Now if you get into rebuilding engines entirely, a spring compressor, ring compressor, ring pliers, c-clip pliers, feeler gauge set, micrometer, and 3/8 and 1/4" torque wrenches are necessary on top of the existing stuff, but those jobs are becoming few and far between given the throwaway nature of most lawn and garden equipment these days.