Measures clutch pack clearance, pump pocket depth and selective washer gaps off a flat 4 inch base, 0 to 6 inch at 0.001 inch.
Clutch pack clearance is the measurement that decides whether a rebuilt automatic shifts firm and lasts, or flares and burns its new frictions. This Accusize 2025-4201 depth micrometer set measures 0 to 6 inches in 0.001 inch steps off a 4 inch hardened base, with six interchangeable rods in a fitted case. It is built for the depth checks a transmission bench does every day: clutch clearance, pump pocket depth and selective washer gaps.
Once a clutch pack is stacked and the snap ring is seated, bridge the drum with the base, run the rod down to the pressure plate, and read the distance. Take a second reading with the pack pressed down, or compare to the snap ring face, and the difference is the clearance. Doing it at three points around the drum shows whether a plate is cocked. A feeler gauge works on open packs, but on deep drums and stacked assemblies a flat base and a screw-thread reading are more repeatable.
Use the factory clearance from the service manual for your unit whenever you have it. Transmission Digest gives a rule of thumb when no value is published: about 0.008-0.010 inch per friction, so a six-friction pack lands near 0.048-0.060 inch. Correct an out-of-range pack with the selective apply plate, pressure plate or snap ring rather than adding or removing plates. For endplay work, our endplay and thrust washer guide and the 4L60E shim selection walkthrough show where the measurement fits into assembly.
It is not tied to one model. Any automatic with stacked clutch packs, selective washers or a pump with gear pockets can be measured with it: GM 4L60E and 4L80E, Ford 4R70W and 5R55 family, Chrysler RE and RFE units, and the import transaxles. The 6 inch range covers deep drums and case-to-thrust-surface depth that a 6 inch caliper cannot reach squarely. Browse the rest of the bench measuring tools on our transmission tools page.
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The depth micrometer head with its 4 inch base, six interchangeable measuring rods covering 0-6 inches, and a fitted plastic case.
Graduations are 0.001 inch. That resolves clutch clearance and selective washer specs, which are normally given in thousandths.
On many open packs, yes. The depth micrometer is easier on deep drums, stacked assemblies and when you want readings at several points around the pack.
Use the factory value for your transmission. When none is published, Transmission Digest's rule of thumb is 0.008-0.010 inch per friction plate.
Add the rod's starting value to the barrel reading. With the 2-3 inch rod, a barrel reading of 0.425 means 2.425 inches.
