BB7A 8-Speed DCT Transmission Overhaul Seal and Gasket Kit

This is the soft-parts side of a BB7A rebuild: the gaskets, lip seals and O-rings you replace when the eight-speed dual-clutch out of a 2015-2017 Acura TLX 2.4L comes apart. The BB7A is Honda's DCT with a torque converter on the front of it, and it is a tight, wet unit — every joint you break open on the bench needs a new seal before it goes back together.

Two problems put this kit on the bench. The first is the obvious one: a leak. The case halves and the side cover weep at the seam, or a shaft seal hardens and pushes fluid past the axle seal onto the subframe. The second is the one people miss. Hardened O-rings inside the hydraulic circuit let pressure cross-leak between clutch feed passages, and the car starts shifting slowly, flaring between gears, or shuddering at low speed while the fluid and clutch packs test fine. Replacing every seal in the unit while it is open is the only way to take that variable off the table.

Work the reassembly in the usual DCT order. Clean every sealing surface back to bare metal — no gasket scraper gouges on the case flanges. Lubricate each O-ring with clean transmission fluid, never assembly grease, so it does not roll or pinch when the shaft goes through. Seat the shaft seals square with a driver that matches the bore, not a socket that catches the lip. Then fill with the correct Honda DCT fluid to spec and check level at temperature, because a dual-clutch punishes an overfill as hard as an underfill.

Note what this kit is and is not. It is an overhaul seal and gasket set. Clutch packs, steels, bearings and hard parts are separate and are inspected on their own.