Advice: Cross Threaded Trans Cooler Lines

Howdy guys, I’ve been stuck on how best to handle this slightly embarassing issue... I cross threaded one of the trans cooler lines in my ‘79 C10 after a few too many brews. It has the stock 305 radiator with integrated trans cooler on the passenger side. I’m just a little too ADHD and inexperienced to figure out the best course of action here.

First off, I can cut the cooler line, add a new fitting, and reflare it. That’s not my worry.

My first and lesser concern is that if I retapped the threads in the cooler, I’m not sure I’ll get a good seal. If it still leaks, I’m back to square one.

My second and more major concern with the retap it plan is the possibility of leftover metal shavings getting into the trans no matter how many times I flush the cooler out. I’d hate to kill a trans trying to save $100.

I also have several external trans coolers of roughly appropriate size laying around in the garage. I should be able to adapt one of them but it will require purchase if additional lines and fittings.

My last option is to buy a new radiator with integrated trans cooler. I remember seeing an amazon link to one for a little over $100 somewhere on the forum but have long since lost track of it.

So what would you guys suggest I do?

IMO....If the lines and fitting threads are still good, may be worth the cost of another radiator vs other methods that may end up being more costly. Go slower with the brews during installation and all will be good. LOL

If all else fails, JB Weld! It ain’t broke if JB Weld can fix it!

I'd just install an external cooler and call it good. The trans will just run a bit cool in the winter, when it's just cruising at speed.

If you can rethread it straight it should seal. The joint seals on the flare, not the threads. The hard part will be getting the tap far enough into the fitting without damaging the flare seat. Use a bottoming tap if possible.

For the chips, attach a regulated air supply to the opposite fitting on the cooler and run a few psi of air through it while you're working on the threads. That will blow any debris out of the cooler.

And remember to wear your safety glasses for this. Not your beer goggles.

As to concern for the seat, a flat bottom tap is available through an industrial supply house (MSC?). I believe it is called a ‘gun bore’ or just a ‘bore’ tap.

Thanks for the advice and suggestions guys. No more beer goggles in the garage for me.

I’m going to eventually try repairing the radiator with a flat bottom tap and air supply as suggested but for now I decided to buy a Spectra CU730 for a quick swap. This is the last piece to getting the truck driving again and I’ve just about run out of patience. The previously mentioned reference was in regard to this post.

DirtyDYT said:

So what would you guys suggest I do?

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I would use a thread chaser before I attempted anything else. They have saved my bacon more than once and are ideal for cross threaded "stickie" situations:

https://tinyurl.com/yacvzmdh

Of course I’d abruptly change plans despite just receiving a fresh radiator!

The external trans cooler looks to be the quicker and easier route with less potential for spillage. It also allows me to reroute the “not quite right” repro cooler lines a little more out of the way and not worry about replacing my custom cut to fit Windstar fan assembly I had installed on the old rad.

See what I mean about being ADHD?

bucket said:

I'd just install an external cooler and call it good. The trans will just run a bit cool in the winter, when it's just cruising at speed.

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Fairweather only for this truck. The heater core is disconnected, the blower doesn’t work worth a damn, and I’d really hate for the body cancer to get any worse than it is.