Help- Transmission Support Nut/Bolt

I just installed some catalytic converter shields. It was super easy, except that on the passenger side, when I went to replace the two bolts that attach the support tube to the transmission support, one of them would not fully tighten. Either the nut and/or bolt is stripped, or I'm thinking more likely, the weld failed that is holding the nut to the inside of the transmission support. The bolt right next to it is fine and plenty tight. I can't access the nut to keep it from spinning, because it's inside the transmission support.

I really don't want to have to take the whole transmission support off. Any suggestions? Am I good with just the one bolt there? I suppose if the nut is stripped then I can just drill and retap it, but I'm guessing that's not the issue.

Thanks.

 

I’d go with one. The real problem is being able to remove it. Maybe if you need it removed it’s going to be cut off

 

I would get it fixed. The one bolt that is tight is bearing twice the load than it was before. I am OCD and it would bother me. And what if aircraft mechanics were ok with leaving a stripped bolt?….. that is where my mind would take me

 

I just had an idea. I have an old combination wrench that I could bend to a right angle and insert in a nearby hole in the support piece that would enable me to hold the nut inside while tightening the bolt.

 

Take note the original welded on nut is prob

Take note that the original welded on nut is usually a square nut, while any other nut you source will be hex and likely a different size for your "custom tool". You may have to contend with weld slag within the support too.

I make my own custom tools all the time.

That reinforcement tube is often left out when installing aftermarket skid plates - so some people think they are necessary, while others think they are not - I have not made up my mind yet.

 

All good points and I hadn’t considered it would be square, but you’re probably right. The weld is probably limited to the lower portion of the nut and hopefully not an issue. Now I find myself wanting a tiny camera to see in there.

As far as whether it’s needed or not, it’s hard to know. I have three bolts all tightly secured and a fourth that is mostly tight and providing some sheer strength, which is mostly what that piece is for anyway.

I appreciate everyone’s feedback.

 

A small flashlight and an equally small inspection mirror will work, yes, the nut is square. Just looked with the above tools.

 

Hey, awesome, thanks. Might have to find one that is easily inspectable to get the size, since now I'm gonna have to use an open ended wrench. Not looking good for my plan, but still gonna try it.

 

I’m pretty sure Toyota uses the same nuts elsewhere. If you have one of those stock splash/skid engine plates take it off to see the size, per thread size like M8•1.25.

 

Yep, yep. What might be easier, if it turns out the weld failed, is to just grind the bolt head off on the bottom side, then make my custom wrench with a regular nut held firmly in place in it, insert a new bolt and boom, done.

 

All depends upon what you see once you have a look.

 

One more thought on that nut. Since you seem capable to build/fab your own tools, make a nut plate out of 1/4-3/8" material. Involves a lot less fiddling with a smallish nut and wrench. I've made my own for various places on this truck.

 

That’s a great idea, so take a piece of plate or strap, narrow enough to get into there but too wide to turn freely, and either tap the plate or I could drill a hole and weld a nut to it.

 

Exactly. Easy peasy and less trouble if you revisit that area in the future. The plate does not have to be large either, welding on a piece of wire to position it works well also.

 

I think this came up weeks ago or similar. Solutions were tapping a piece of bar, welding a nut to bar, or rivnut. I have no experience but it sounds similar to solving bolt on slider problems. FWIW.

 

UPDATE:
Feeling like a fool, but also feeling pretty good about myself for having fixed it.

When I did the job initially I left the bolt in there, loose, because I was running late for some other business. Before assuming the nut weld had failed I should have confirmed it. I just thought that it was more likely since I knew I hadn't cross threaded the bolt. Turns out the bolt was stripped. My best guess is that when I reinstalled it the threads got smashed on the crosstube and support on the way in. I should have kept everything hand tight in that area before tightening further.

So I tapped the hole, one size up from 5/16" to 3/8". I had to use coarse thread since that was all I had on hand. Now everything is right in the world, or at least with my Tacoma.

Hopefully, someday down the line, if someone does need to replace a nut inside such an area, they'll find this thread and our mental exercises will not be for nothing.

Thanks especially to Toycoma2021 for all the ideas.

Also, love the Cali Raised cat shields. Such an easy install. Hah! But really, except for this they're really nice.

 

Sacrilege, putting a non-metric fastener on a metric vehicle!

 

I know, I felt wrong but had to be done.