Accusize EE20-2416 Dial Bore Gauge Set 1.4-6 in .0001

A dial bore gauge is how you find out whether a worn transmission is worth reusing parts on. On the bench it reads the inside diameter of pump bushings, drum and rotor bores, servo bores, case bushings and stator support bores down to a tenth of a thousandth, so you can measure actual wear and out-of-round instead of guessing by feel. Set the gauge to size with a micrometer, run it through the bore, and the needle tells you exactly how far off the bore has gone.

This Accusize EE20-2416 set covers a 1.4 to 6 inch range with 0.0001 inch graduations, which spans the bores you deal with on GM, Ford, Chrysler and import automatics. It uses an AGD Group 2 dial indicator with a 0 to 0.05 inch travel, carbide-tipped contact points that hold up to repeated use, and self-centering measuring heads so the reading squares itself in the bore. Fifteen anvils and four spacers (0.5, 1.0, 2.0 and 3.0 mm) let you dial in the exact size you are checking.

The indicator locks to zero with a bezel lock, the handle is chrome plated with an insulated grip, and the set ships with an extension holder and a fitted case. Pair it with a good outside micrometer to set the master dimension and you can qualify a used pump body, drum or case bore in under a minute rather than scrapping usable hard parts on a hunch.