C6 Transmission cooler line adapters in trans case?

[Ataylor]

Hi,

My transmission cooler lines have rubbed together and look dangerously thin. I was thinking about replacing them with braided hose. I have read the adapters that are in the transmission case are 1/8 npt. Has anyone ever taken these out and replaced them with other adapters? I'm just worried that once I get them out I won't get the adapters to seal again.

Thanks for any advice,

Archie Taylor

 

[icanfixall]

They are not 1/8 national pipe. They are 5/16 and probably a machine thread with an o-ring seal on one of them. On my E4OD the line returning to the rear of the trans is the from cooler line. Where it enters the trans is a special fitting thats a check valve. Without that check valve the torque converter will drain down when the engine is shut off. Then it takes plenty of time to refil the converter before you can drive off... Not a good thing to be doing. My trans oem was 5/16 lines but I upgraded to 3/8 lines braided stainless steel when I installa a rebuilt Jaspers trans. Got many good miles out of that. Now the BTS E4OD kicks a$$ with those same 3/8 lines. I think in around 92 the lines were all upgraded to 3/8...

 

[Ataylor]

Thanks Icanfixall. That would make sense that they are o-ring fittings and not NPT because the fittings are flush with the trans case. I would think that NPT would have a little thread showing since most of the time the fittings don't bottom out before they jam tight.

Archie

 

[icanfixall]

On my e4OD the rear trans fitting needed to be drilled out for the 3/8x18 pipe fitting to fit. Turns out it was something called straight pipe threads instead of the normal tapered pipe threads. Those straight pipe threads are found on electrical conduit pipe and you never want to mix up those fitting. Tapered pip threads seal by the thread taper. The straight pipe threads can't seal unless an o-ring is used. Another example of funny threads is the injection pump inlet brass fitting. Its got a 1/x20 bolt fine thread fitting and an o-ring going into the pump end. Knuckledragger figured that out for me a few years ago. Thanks Mike for that......

 

[Ataylor]

I took the adapter fitting out of the transmission and it is defineatly straight thread. It is an odd one. I thought it was 9/16-18, but it is not. This was all before I saw Icanfixall's last post. The 9/16-18 measures 0.565", but the transmission cooler adapter measures 0.525" with 18 pitch threads. I will look up straight pipe thread.

Does anyone know if they make an adapter to go from straight pipe thread to AN fittings? Retaping the trans case isn't an option. I just had the transmission rebuilt and I don't want to risk messing up the case. I just want to fix the "almost" rubbed through hard lines and though now would be a good time to upgrade.

Thanks for any info anyone can offer,

Archie

 

[sassyrel]

The straight pipe threads can't seal unless an o-ring is used. ....[/QUOTE]

mmmm..if the back side of the nut,,and the trans surface,,are flat,,a dead soft copper,,or aluminum washer will seal it also..

 

[spg]

Leave the original fittings in the case and use AN to inverterted flare fittings to attach the braided steel lines and fittings. PM me if you have any questions