So I have a bunch of stripped out holes on my 904 transmission pan. The last person to install the pan used a crap-ton of RTV, presumably to keep the thing on when at least half the bolts can't be torqued properly.

I assume that the best course of action is drilling the stripped holes out and installing helicoils. I'm wondering if anyone here has done this before and can offer advice on what type to use, how best to install them, etc.

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Somehow I ended up owning three 1964 slant six A-bodies. I race one of them.
Escape Velocity Racing

Heli-coils are rather easy. The directions are simple and clear. Drilling the hole perpendicular to the pan rail and starting the tap square is all you need worry about.

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Joshua

Just out of curiosity, why wouldn't you just tap them up to the next size? The transmission casing is aluminum.

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1964 Dart GT

Bolts may not fit the pan itself then, especially with washers. The distance to the inside edge or outside lip is very small. Even smaller when using aftermarket cast pans.

You could fit in allen head bolts if you want to go up in size on the threads and use SAE washers rather than the wider USS washers. You would probably want to change them all however. But Heli-coils should be pretty easy in that location; check one to see if there is enough undisturbed meat left in the old hole to hold the helicoil.

I am just thinking about installing that many helicoils, and is the trans in the car?

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1964 Dart GT

I have helicoiled trans's while the pan is off but the trans is till in the car.

Just try to keep the shaving out of the Valve body area and it's fine


Greg

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http://www.youtube.com/hyperpack

Trans is in the car. It wasn't too difficult to do with all four corners of the car jacked up. The only really critical part is the initial drilling. As long as you drill the hole straight, it's very difficult to screw up the tapping operation, especially since the case is aluminum. Inserting the helicoils into the larger-tapped holes is also very easy.

I mainly went with helicoils because I wanted to keep the bolt sizes uniform while also reducing the chance of stripping the holes again in the future. Of course, because I'm lazy and didn't have a lot of time to spend on this, I ended up only helicoiling the ones that were completely stripped out. The others I torqued in steps to see when the pan stopped leaking. Still had to run some RTV along the front edge of the pan to stop a drip after I got all the bolts as tight as I was willing to gamble. It appears to be holding now. Just has to survive one more race, then this whole drivetrain is getting a "proper" overhaul.

_________________
Somehow I ended up owning three 1964 slant six A-bodies. I race one of them.
Escape Velocity Racing