Dial Bore Gage Set 0.7-1.5 in for 4L60E Bushing Bores

A two-point dial bore gage that reads from 0.700 in to 1.500 in with 0.0005 in graduations and an 8 in measuring depth. That range is exactly where automatic transmission bushings live: the stator support and pump bushings in a GM 4L60E and 4L80E, the direct drum and reaction shell bushings, the extension housing bushing, and the case bushings on a Ford 4R70W or a Chrysler 46RE. Fowler model 52-646-100-0, sold with the indicator, carbide-tipped anvils and a fitted case.

How it gets used on the bench: set the gage to a known size first, either with a setting ring or by holding a micrometer at the nominal bushing bore, then zero the indicator at the low point of the sweep. Drop the gage into the bore and rock it slowly. The needle reverses at the true diameter, and that reversal point is your reading. Take it at two depths and at 90 degrees to itself. The difference between those readings is your taper and your ovality.

This is the tool that tells you whether a low line pressure or a converter-related shudder complaint is really a worn pump bushing letting the stator support walk. A bushing that measures 0.002 to 0.004 in over its bore, or that shows more than about 0.001 in of out-of-round, is the leak path that a rebuild kit alone will not fix. It is also how you verify a new bushing after you drive it in, since bushings size down when they are pressed into an out-of-round housing.

The handle is chrome plated with an insulated grip so hand heat does not walk the reading, and the anvil contacts are carbide so they hold size after repeated passes through cast aluminum and steel bores.