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-Coils™, or equivalent. This repair consists of drilling out the worn-out damaged threads. The hole is tapped with a special Heli-Coil tap, or equivalent, and a Heli-Coil insert, or equivalent, is installed 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.