6T40 Transmission Pump Seal Installer Set, 3-Piece

Three-piece adapter set for the front pump stator support seal on GM six-speed transaxles: 6T30, 6T40, 6T45 and 6T50, 2014 and newer, as found in front-wheel-drive and all-wheel-drive Chevrolet and Buick cars and crossovers. It is the OTC 6743, made in the USA with global parts, and it is the equivalent of the GM special tool DT-51191. Shipped weight is 1.19 pounds in a 7.64 x 4.33 x 2.6 inch box.

The set has three pieces and each one does a separate job in sequence. The seal protector slides over the stator support so the sharp edge of the support does not nick or roll the lip of the new torque converter fluid seal ring as it goes on. The installer pushes the seal square to its depth instead of cocked, which is what happens when you drive it with a socket. The sizer then goes over the installed seal and resizes it back down to the correct bore diameter so the torque converter hub slides in without shaving the seal on assembly.

This is the step that decides whether a rebuilt 6T40 comes back on the hook. That converter seal ring runs on the converter hub and carries line pressure to the converter circuit. If it is stretched, nicked, or sitting proud after install, you get low converter charge pressure, a converter clutch that will not hold and slips under light throttle load, a P0741 or P2757 in the module, and front pump area seepage down the bellhousing. A seal sized by hand or driven in with a socket usually reads fine on the bench and fails once the unit is hot in the car.

Use it during unit overhaul with the pump on the bench, before the converter goes on. The seal ring is not included; buy the correct ring for your build and use this set to put it in right.