Time-Sert 1215C M12x1.5 Drain Plug Thread Repair Kit

This is the Time-Sert 1215C kit for repairing stripped M12 x 1.50 drain plug threads in an aluminum transmission pan, differential cover, or oil pan. Unlike a coil insert, a Time-Sert is a one-piece solid steel bushing with its own external thread. You drive it in, then the installation tool cold-rolls the bottom of the insert outward so it locks into the casting. The result is a full M12 x 1.50 thread that takes a normal drain plug and torque spec, and it seals against fluid instead of weeping through a coil.

M12 x 1.50 is the drain plug thread used on a large share of transmission and driveline castings, including many ZF 8HP pans, GM 6L80 and 6L90 pan plugs, aftermarket deep pans with a drain boss, and a lot of rear cover drains. It is also the thread that gets ruined first, because the plug goes into soft aluminum and gets overtightened at every service. Once the threads pull, the usual choices are a new pan or an oversize self-tapping plug that only buys you one more shot. This kit puts the original thread size back in the casting permanently.

Bench sequence: drill the damaged hole with the supplied bit, counterbore the face flat so the insert flange seats below the sealing surface, run the tap using the tap guide to keep it square to the boss, clean the chips out completely, then thread the insert in with the installation tool until it bottoms and the tool flares the skirt. Work with the pan off and inverted if you can so no chips fall into the case. The kit includes the drill bit, counterboring tool, tap, tap guide, insert driver, and five inserts, so you get five repairs out of one kit and can buy inserts separately after that.