2001 S80 2.9 4T65E; safe to heli coil damaged pan bolt threads?

[DanSC]

Short question: are heli coils a safe repair for transmission pan bolt hole threads?

I have a slow transmission leak that is almost certainly due to a few transmission pan bolt holes with damaged threads. I am sure I damaged the threads when I switched to a pan with a drain plug; I just don't remember damaging them...

The bolts stay in place, but they don't torque down without spinning.

I am thinking of using heli coils to repair the damaged bolt holes in the transmission case. I have experience with heli coils, and I'll use a lift for the best drilling angle.

This post is a reality-check before I start drilling into the transmission case. Is there any reason I should not repair these bolt holes with heli coils?

[DanSC]

Replying again with an late update in case anyone finds this. The case had plenty of aluminum for heli-coils. It also has plenty of aluminum for E-Z LOK threaded inserts, and I highly recommend using those instead of heli-coils.

[MoVolvos]

Replying again with an late update in case anyone finds this. The case had plenty of aluminum for heli-coils. It also has plenty of aluminum for E-Z LOK threaded inserts, and I highly recommend using those instead of heli-coils.

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It's been awhile since changing the filter and adding a Trango shift in the 4T65E of the 03 S80 T6. Do you think it would have been easier to tap it? Not sure if the pan hole could accommodate the next size bolt without enlarging the hole?
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[DanSC]

It probably would have been easier to tap the hole to a larger size. I mostly don't like having a bunch of odd non-standard nuts and bolts on the car.