HeliCoil for aluminum Auto Trans thread repair.

[HotRodPC]

Hopefully this will add some hope for some of you. VAL has a stripped pan thread right on the corner bolt of his 700r4 from recently taking the pan off and on several times while diagnosing TCC lock up.

I have used many many HeliCoils for Automatic Transmission thread repair. I've also used one to repair and Edelbrock Torker ll intake manifold for a stripped out thermostat bolt. I've never had one come back failed and all have been a permanent fix and made the threads better than new.

I suggest buying the complete HeliCoil Kit for the desired or needed thread pitch and size. Then I keep my kits together and DO NOT use the drill bit for anything else. The drill bits are the hardest thing to come by since they are always going to be a real wierd size uncommon bit, so it's not likely you'd have that bit in a common collection set of bits. So don't use the bit except for this purpose and then you won't wear it out near as soon and it will be ready when you need it. Once you buy the kit, you can buy just the HeliCoil refill pack and it's much cheaper than buying the whole kit.

 

[HotRodPC]

So here I was torquing down the front pump bolts on my bro's Th350 trans build for his El Camino. Didn't get even half the torque and it let lose. And here's what the bolt looked like when I pulled it out.

 

[HotRodPC]

I pulled the pump off, but didn't want to have to pull the rest of the transmission apart, so I stuffed it full of a bath towel to catch and trap any shavings that might have jumped out of the hole. Remember, this is aluminum, so you can't use a magnet to suck out the shavings. Very critical to keep the shavings out of the transmission. This goes for it you're drilling out for a repair in the pump section or the valve body section. Pan section, you're probably OK, especially if you're drilling overhead. The shavings should fall to the ground, but be sure to wearing safety goggles.
Carefully drill the hole only as deep as necessary with the supplied drill bit with your kit. BTW, the kit will tell you what size drill bit you need. So if you do eventually wear out the bit, you can go buy just the bit and replace the bit in your kit. I've had to do it before on one of my kits I used it so much.

 

[HotRodPC]

In this case, next step is to remove all the shavings. I used a shop vac with a small tool accessory kit to draw the shavings out of the hole. Using air to blow it out isn't a bad idea either if you can assure none of the shavings are going to get blown back into your project if it's critical like this is.

Here is the freshly drilled and cleaned out hole, now ready to run the tap that came with the kit to install the oversize thread insert.

 

[HotRodPC]

Keeping the towel or putting the towel back in the transmission tunnel because even the tap is cutting aluminum and does also make shavings. Once you get the hole tapped. Now spin a HeliCoil onto the installer tool. Be sure the run the Coil all the onto the tool as far as it'll go. If the Coil happens to be longer than you need, then pull a coil or 2 off the top of the complete coil, but not the bottom. Notice the bottom of the coil has a stop built into and that's for the installed tool to be able to push the coil threads.

 

[HotRodPC]

Here's a better angle of the Installer tool.

 

[HotRodPC]

Once the Coil is bottomed out into the hole and threads you cut, or at least below flush of the surface where it's not sticking up past whatever you're bolting to, then you can back the installer tool out counter clockwise and the coil should stay in place.

And there you have it. A brand new thread. As you thread the bolt into the new coil, it will push the tab on the coil out of the way. If it's a situation where there isn't enough room in the hole for that piece, then you get something and push that tab up and/or down til it breaks off, but I've always just left it it works as a lock for the threads and the bolt.

 

[HotRodPC]

And now back to regularly scheduled programming. Installed the pump and torqued all the bolts. Rolled it over and installed the valve body and completed the install. The transmission worked fine and made several trips to and from TX and was working perfectly 2 years later when the car was hit and totalled and ended up in Chevy heaven.

 

[HotRodPC]

Here is a search at Amazon.com for several of the different ways and sizes to buy the HeliCoil repair kits.

http://www.amazon.com/s/ref=nb_sb_s...l thread repair kits&sprefix=helicoil,aps,355

O'Reilly's stocks them too.

http://www.oreillyauto.com/site/c/search.oap?keyword=heli-coil+inserts

 

[VAL]

Nice! Gonna order a set from amazon. I was just gonna tap it out to the next size, but something about not having all 16 pan bolts the same size, would just ******* Gnaw at me forever. OCD?

 

[350runner]

Paint it bro