I am redoing the hoses, going to 3/8" steel lines, into an external cooler, and back. What size/type of fitting are those, going into the C4?
you need to be careful here. some are common 1/8"npt some are 1/4" npsm the problem is if you put a npt in to a npsm you can crack the case. check this out http://www.ehow.com/info_8723422_difference-between-npt-npsm.html
although I've heard of many deleting the o-ring and using pipe thread with sealant.. I'd go with what was intended to be used which is the straight thread that Bryant mentions above. There are plenty of conversion parts around the net too. This guy does them custom. http://raceabilene.com/kelly/hotrod/trans.html
I will pull off the fittings and take them in to the hydraulic shop I use and make sure we get the correct fittings. No reason to reinvent the wheel, here. I was hoping we knew ahead of time, since I am in town today and could buy them now, but since there are potentially two different types, I will wait until I get the original ones off.
I currently have pipe threaded chunks in there, and they are working, but these are supposed to thread in deeper with straight threads, and an o-ring at the bottom, aren't they?
5/16", I think. Going to 3/8" because I just bought 50' of it, and figured, "Why not?" with all the extra tubing I have laying around. If you will notice, from this picture... Either 5/16 or 3/8...both are overkill. That hole is TINY!!! The transmission cooler I have has huge inlet and outlet holes, 3/8" pipe threaded, so a larger tube isn't much of an issue on that end.
Yeah it's small but with pressure they'll be quite a bit of flow, at least the line isn't a restriction...
The cooler has pretty nice large holes... Check out this surprisingly nice cell-cam photo of the inside of my new trans cooler!!! Should hold a large amount of fluid as it lets it sit and cool over all those vanes before being shoved out the far hole and back to the transmission.
