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Trans cooler quick disconnect.

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Does anybody recognize this fitting in the pic, and know what pipe size the thread is? I believe the threads are 1/4" BSPT (British Standard Pipe Thread) but the threads are flat at the top of each thread and there seems to be a small groove at the top of the thread. The second pic is the OEM cooler for an Auto equipped 03-09 CTD, it is what the fitting connects to.
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It's hard to tell by the picture but those threads loook straight. BSPT is tapered and uses the threads to seal. Is there any kind of sealing washer at the end? British Standard Parallel Pipe uses straight cut threads and some type of crush washer to make the seal.
 
There is a slight taper to it, which seems normal for a BSPT, the BSPT is not as pronounced as NPT. Also the thread you mentioned is BPPT (British Parallel Pipe Thread) and BPPT does have a flat surface at the bottom of the threads for a crushing washer to seal, like a spark plug would have. The difference between BSPT and NPT is the angle of taper with BSPT being 55* vrs 60* for NPT.

I had a similar issue with my EGT sensor, the sensor turned out to be 1/8" BSPT, and the company who sold it to me confirmed it to be NPT as they advertised. They even sent me a new one, claiming they had a batch of sensors that were smaller in size and the one they sent was a good one, that turned out to be the same threads. So I purchased an 1/8" BSPT tap and drilled and tapped a test tapping into aluminum, it turned out to be 1/8" BSPT. The taper seemed to be strait as well, and is why I questioned it at the time, and tested it into an 1/8" FNPT and it did not tighten as it should have, which would have caused an exhaust leak. The sensor is perfect now in my exhaust with the proper threads tapped to 1/8" BSPT.
 
That fitting looks like it has been cross threaded and bottomed in a blind passage, but, that could be normal. I thouhgt the those connectors were 1/4 NPT on the auto trans but I have not checked that for many years. That could have changed at some point.
 
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It can't be NPT, and it doesn't look like its been cross threaded, although it was used by a Dodge transmission tech to test his transmissions connected to a 1/4" NPT fitting, which didn't fit correct, but he did use it for short periods at a time. I found this image that makes me think its BSPT.

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The question is which transmissions. I do not know what the RFE's are using or the NAG's but considering the overseas influence it is probably a metric thread where the 47\48's are an NPT. If you are trying to source a fitting for the cooler I would have custom lines made with the correct fittings to attach to the trans where it needs to and not try to match some of these oddball fittings.
 
The question is which transmissions. I do not know what the RFE's are using or the NAG's but considering the overseas influence it is probably a metric thread where the 47\48's are an NPT. If you are trying to source a fitting for the cooler I would have custom lines made with the correct fittings to attach to the trans where it needs to and not try to match some of these oddball fittings.
Its not going to mater which trans, because its not going to connect to a trans. I'm adapting it to 1/4" NPT or 3/8" NPT for my Stainless braided hose with russell fittings.
 
If it was me I would cut the disconnects off and swedge or solder on a standard fitting and toss the oddball stuff. Would make it a lot easier to make up lines, if I understand what you are trying to do.
 
I want the ability to quick disconnect the lines from the cooler. I have put a lot of thought and patience into my G56 trans cooler setup, and the last of what I need is the adaptor for my quick disconnect fitting. I was hoping someone could identify that fitting. I'm going to order that fitting I linked too and hope it fits the threads.
 
Found out the threads are indeed 1/4" NPT. Thought about rethreading them to NPT, seeing how they seemed larger in diameter. But the pictures don't lie.

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