Aluminum Thread Repair

STANDARD PROCEDURE - ALUMINUM THREAD REPAIR
Damaged or worn threads in the aluminum transmission case and valve body can be repaired by the use of Heli-Coil, or equivalent. This repair consists of drilling out the worn-out damaged threads. Then tap the hole with a special Heli-Coil tap, or equivalent, and installing a Heli-Coil insert, or equivalent, into the hole. This brings the hole back to its original thread size.
Heli-Coil, or equivalent, tools and inserts are readily available from most automotive parts suppliers.