Helicoil on a transmission pan bolt, or drill and tap for next size up?
 

Hello,
So the previous owner of my truck had dropped the transmission pan at some point to drain the fluid, which is fine, but the problem is, he lost 2 of the transmission pan bolts, and used similarly sized self threading screws instead... Transmission is the 46re. When I bought the truck, I noticed the leak but figured I'd be replacing the gasket and filter on it anyhow, so I didn't think to look at the bolts. Anyways, the transmission has leaked the entire time I've owned the truck, and I'm getting tired of pouring more transmission fluid into it. I'm going to fix the leak.

So, my question is, would I be better off by installing helicoils in the 2 bolt holes and then installing the correct size bolts, or should I drill the hole out and go the next size up? Just wondering how I should go about this.

I personally would use the helicoils, because I would want all the bolts to be the same.

Yeah, that's the draw to using the helicoils.

Anybody know off hand the thread size and length of the bolts?

Should be listed in the parts manual. Or, just take one with you to the parts store, and they should have a gauge.

Yeah... I was just trying to avoid taking one of the bolts out in the parts store parking lot.

Little bit of googling and found this

Awesome! Thanks!

I would first try and get a tap of original size bolt and run thru the 2 bolt holes you describe as sometimes that can straighten threads up and could get proper size bolts since you say they were close to original size , personally if I needed to I would tap to next size up , the 2 different bolts are not a big deal and stronger than helicoils in my opinion and would be my last option .

The pan bolts aren't heavily torqued, so, heli-coils will work just fine.

Which ever way you choose to go is going to involve drilling and tapping.
Drill and tap for the heli-coil or drill and tap for the next size larger bolt.
The only advantage, if you go with heli-coil and use the original size bolt,
is only one size socket/wrench required to remove/install the pan.