Aluminum housing thread repair HELP

Anybody know how to repair stripped threads on a transmission housing?
I know I can sleeve it, but how is that done and how much do the kits cost?
I have a 700R4 GM transmission in my Explorer and a NP231 transfer case. The bolts were too short that came with the Advanced Adapters kit and pulled out of the back of the transmission, taking the threads with them. All four holes are stripped. I guess I need to thread them with a steel insert?
I was going to take it to a transmission shop, but I am afraid to tow it over there because the adapter is what holds the rear of the transmission in and as I said, all the bolts are stripped.

Get a Helicoil thread repair kit.

If there is enough material left -- I would drill and retap for a larger bolt (and go with the finest thread you can find for optimum strength). But really, we need pics fist

A heli coil will make it stronger than it ever was. Since you need to tap either way-That is what I would do.

jtsmith said:

A heli coil will make it stronger than it ever was. Since you need to tap either way-That is what I would do.

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I agree with the heli coil being stronger, but I have never done one (or four). And tapping the holes for larger bolts won't work because the adapter would have to be drilled out too, and its a nicely machined piece.

How hard is it to get the hole drilled out straight? I would hate to screw up.
Is the kit cheaper than just taking it somewhere and paying them to do the repair?
I figured out I can strap the adapter plate in place for the short trip to the transmission shop.

IZwack said:

If there is enough material left -- I would drill and retap for a larger bolt (and go with the finest thread you can find for optimum strength). But really, we need pics fist

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Visualize a aluminum hole, that is exactly what it looks like

It is pretty easy if you take your time, and work slowly.

Much cheaper to do it yourself. I would be surprised if the new bolts and the helicoil kit together were 40 bux. It should come with a tap, and the tool to insert it.

If you decide to do it yourself, before you thread the Heli-coil in place, apply some red loc-tite to the outside of the coil, it will lock them to the casting you just threaded.

Thanks fellas.
I love this web site.

I forgot, one more thing;
What type of sealant should I use for the back of the transmission, adapters and where it joins up with the transfer case?

BKennedy said:

Visualize a aluminum hole, that is exactly what it looks like

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I'm trying..

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I failed.

IZwack said:

I'm trying..

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I failed.

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My wife just asked me what I am laughing at.

BKennedy said:

I forgot, one more thing;
What type of sealant should I use for the back of the transmission, adapters and where it joins up with the transfer case?

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I used right stuff for my adapter mating surfaces, which is now made by permatex. It comes in a chease wiz type can or what looks like a small caulk gun type thing..

That stuff seems to be the best sealant..

~Mark

Maniak said:

I used right stuff for my adapter mating surfaces, which is now made by permatex. It comes in a chease wiz type can or what looks like a small caulk gun type thing..

That stuff seems to be the best sealant..

~Mark

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Thanks

IZwack said:

I'm trying..

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I failed.

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bunnies again?

Okay, I got a 'Perma-Coil" kit in the right thread pattern. It wasn't that hard, only had problems with tapping one hole. The tap kept trying to go in crooked. I was more patient than the tap, so I won. I called the company because the coil inserts were too short. Turns out, you can stack them, and cut them down to fit. So, now I have well over an inch of stainless steel threads in the transmission housing. I fabbed up a "torque arm" today, which came out pretty good, if I say so myself. Got the adapter and the transfer case in, then had to go to the ranch and to a party this evening so I am finished for the day. I cranked those housing bolts down real tight, much more than the recommended 25 foot pounds, with a good slathering of blue lock tight to set the housing to the insert to the bolt. Did not want to use the red stuff in case I ever needed to get the inserts out, and the company did not recommend using it. Won't know if the transmission is okay until I get it filled up with fluid and tested in a day or two. Have to wait 24 hours for the sealant to set anyway. I ended up using the Permatex "Ultra Black" at the advice of a transmission guy and a few mechanic friends.
Found out the cross member that was done by my friend Jay Miller is 3/16" thick 1-1/2" tubing. I guess I don't have to worry about that twisting or bending.
Thanks for the help, I will let you know if it works.

Filled it up with fluid and it seems to shift fine. Might have stretched the transfer case shifter cable because it doesn't feel the same, but seems to work. No leaks. I am taking it on a 20 mile road trip tomorrow to make sure its not gonna die.

A few pictures of the "torque arm" I created.

Thats beef Mr. Kennedy!!

IZwack said:

Thats beef Mr. Kennedy!!

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Watching you guys over the years breaking some heavy duty stuff on the trail has made me into overkill. You even got me thinking a Dana 44 won't be strong enough when I haven't ever broken my ARB'd TTB Dana 35.