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Radiator fittings - transmission circuit

anthrax323

NAXJA Forum User
Location
San Antonio, TX
Hey guys,

I've looked high and low but can't seem to find what I'm looking for... Does anyone know the inlet/outlet threads for the transmission circuit of the factory radiator? I think the upper fitting is a 5/8-18 male, but will confirm that with some hardware later today.

I believe the lower fitting is a 3/8" barb, but am not entirely sure on this (and would like to know the thread on the radiator itself)... My goal is to use 100% AN threaded hoses throughout the transmission cooling system, so I'm trying to piece together the long list of crap I need to order.

Thanks in advance!
 
PM Talyn. He did the entire circuit in AN's and kept the stock cooler (rad) while adding an additional stacked plate one up front.

When I get around to doing mine, I'm going to totally bypass the stock sad excuse for a cooler.
 
When I get around to doing mine, I'm going to totally bypass the stock sad excuse for a cooler.
Don't forget, it's also a warmer for cold weather and you being from MD have cold weather. That is unless you don't wheel in the winter.

Just use an aux cooler with a bypass, either automatic or manual and satisfy both needs.

Happy wheelin.
 
PM Talyn. He did the entire circuit in AN's and kept the stock cooler (rad) while adding an additional stacked plate one up front.

When I get around to doing mine, I'm going to totally bypass the stock sad excuse for a cooler.
I'll reach out to him and get his thoughts. Looks like I'll probably end up needing to use a 3/8" hard-line-to-AN compression fitting adapter for the radiator circuit return.

Don't forget, it's also a warmer for cold weather and you being from MD have cold weather. That is unless you don't wheel in the winter.

Just use an aux cooler with a bypass, either automatic or manual and satisfy both needs.

Happy wheelin.
The climate in which I wheel varies dramatically (live in south TX, but drive to CO a couple times per year - usually wintertime), so I'd like to keep the stock radiator circuit to help warm up the transmission.

Grimmjeeper did a write up on using AN fittings. But bypassed the radiator. Still may be of help
Yeah, I found the thread in question (here) and it has a lot of the info I need (especially for the transmission inlets/outlets - M14x1.5). It just looks like I'm trying to be special as usual, creating some headaches along the way. If I would just stick with barbed fittings, this would be considerably simpler.

I'm still tempted to go ahead and replace my radiator while I do all this considering I have 190,000 miles on the clock and had a small leak spontaneously seal itself about a year ago (the leak was created when shoehorning my condenser out without removing the radiator), so I think I should go ahead and replace the radiator anyway and figure it out on the bench (but that starts a whole other conversation about what radiator to buy, which seems to have thousands of differing opinions).
 
On the CSF radiator I am running the bottom line is brazed on and can not be removed. I still have a factory QD there, but I will eventually change the radiator. On the upper line I kept the hard line and replaced the QD end with an AN fitting.
 
Yeah, I found the thread in question (here) and it has a lot of the info I need (especially for the transmission inlets/outlets - M14x1.5).

just wanted to mention that it's not just a m14x1.5, it needs to be the o-ring sealed type. The threads in the trans are not tapered like pipe thread, no o-ring no seal.
 
On the CSF radiator I am running the bottom line is brazed on and can not be removed. I still have a factory QD there, but I will eventually change the radiator. On the upper line I kept the hard line and replaced the QD end with an AN fitting.
Thanks for the info - the bottom line on the factory radiatior appears to be removable, but looks like a jam nut... Need to pull it off and figure it out. How'd you replace the upper QD with an AN fitting? On the radiator itself or on the OE hard line?

just wanted to mention that it's not just a m14x1.5, it needs to be the o-ring sealed type. The threads in the trans are not tapered like pipe thread, no o-ring no seal.
True - I saw that but failed to mention it here. Definitely an important detail :)
 
Another thing you could do to save some cash... Instead of buying the an fit tins like I did you can buy steel hose barbs and weld them to the disconnect fittings. My brother just did this and I think it cost him 5 bucks.
 
Time for a hell of a dead-thread resurrection.

I'm finally moving forward with the AN conversion, as my mini-stroker build is nearly complete. My attention has turned back to the radiator fittings, as everything else is straight-forward (and laid out above).

The lower spring-lock fitting was easy enough, and I even found it locally:

Russell 640850

Unfortunately, the upper is still giving me grief. At this point I'm 99.999% sure it's a 5/8" OD flare (male) fitting, and nobody makes automotive hose ends from what I can find. I'm sure I could stack together a set of adapters (flare -> NPT -> AN) but I'd like to avoid that if at all possible. Fitting can't be removed/changed without cutting and/or brazing, unfortunately.

Anyone tackled this since I initially posed the question 6 years ago? I can't find any indication that I reached out to Talyn, so I'll do that now too.
 
No dice unfortunately. The transmission fitting in question is a 3/8” ID coarse-thread flare fitting, basically what you’d find in some water and gas plumbing applications... so I’d need a female-to-male adapter. I do appreciate the link, though!

A few minutes ago, I had a bit of a revelation... assuming -6AN 90° hose ends are 3/8” ID hard line, and assuming I find an end with long enough legs, I can cut the 37° flare off, remove the -6AN female nut, throw on a 3/8” 45° flare nut, and flare the tube to 45°. I’ve got an orbital flare tool for AC lines which should work, provided I have enough line to get the block on it.

Seem reasonable?
 
Found another option:

https://hydraulicwarehouse.com/1-2-wire-hose-couplings/328-female-90-deg-bent-tube-swivel.html

Called and confirmed it's a 5/8-18 thread, 45 degree seat female end (SAE 3/8" flare fitting in the hydraulic world, apparently). Ordering one to see if it'll work with any forms of AN-style hose when it comes time to crimp it... Being a hydraulic shop, they're not too well-versed in PTFE hose applications (let alone braided), so they were hesitant to guarantee the crimp end work work for this application. Given the low pressure requirements... I guess we'll find out.
 
Then it has to be this one unless you have something totally modidied.
https://www.holley.com/products/plu...ction_adapters/inverted_flare/parts/991946ERL
Nope... Wish it was, though.

IMG_4904.jpg


IMG_4909.jpg


Fitting in question is the upper transmission fitting, left side of pic. Removed the nuts securing both the upper and lower, and found they were just for stabilization. The fittings themselves are not removable.
 
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Thanks for all the tips man - got it sorted!

First things first: it is definitely a 3/8" standard 45° flare fitting. Picked a couple styles up at Home Depot a few minutes ago:

flare_1.jpg


flare_2.jpg


So, worst-case scenario, I'll grab an appropriate -6AN hose end (ideally a long-drop 90, but something like this might still work), cut the 37° flare off, remove the -6AN nut, install the nut above, and flare it to 45°.

I'm also waiting on this hydraulic hose end to arrive, as it might be a more straight-forward solution depending on my luck with the re-flaring approach above.

Also, if the fitting itself is too deep to allow a good seat on the flare (which is a mild concern at this point), I can just cut the old factory transmission line and re-use its flare nut.
 
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