AUTOVIC Ford 10R80 Sealing Ring Resizer Tool Set (3-Piece Input Shaft Resizers)

Anyone who has rebuilt a Ford 10R80 knows the input shaft sealing rings are where a good build can quietly go wrong. Push the shaft into the drum with the rings even slightly oversized and you either tear a ring or leave it wide, and either way you lose the clutch apply pressure that makes the unit shift the way it should. Resizing the rings before assembly is the step that separates a transmission that comes back solid from one that comes back on a tow truck.

This three-piece set is cut specifically for the Ford 10R80 family, the ten-speed found behind the 2017-and-up F-150, Mustang, Expedition, Ranger, and a long list of other Ford and Lincoln trucks and SUVs. You slide each ring onto its matching resizer and let it compress down to the correct diameter, working from the furthest ring in first so you are not fighting rings you already set. Lubed up with assembly gel and fresh ATF, the rings drop into their bores without catching.

The resizers are molded from a tough, slick plastic that squares the rings down without gouging or scoring them the way a metal edge can. It is the kind of small, specific tool that is not on the shelf at the parts store but saves you a second teardown. One note from the field: one of the three pieces also happens to fit the GM 6L80 and 6L90 input shaft rings, so it doubles up if you work on both. Ships from the USA.