TH350 Inlet/Outlet
 

On a TH 350 transmission what is the inlet and outlet thread size for the trans. lines? I always thought they were 1/4 pipe but I am not sure. Anyone know?

Re: TH350 Inlet/Outlet
 

1/4" NPT is correct. Just keep in mind that most NPT to AN adapters (Aeroquip, Earl's, XRP, etc.) are actually NPT tapered pipe fittings. Be very careful tightening these type of fittings into the case since you can break the case in this area if you get carried away with a wrench.

Re: TH350 Inlet/Outlet
 

If you are going to use braided hose for cooler lines , use the original brass fittings that were in the trans along with Aeroquip FCM 2111 fittings. They are1/2-20 inverted flare to #6. This will allow you to attach #6 hose to the trans. I know these fitting are also available from Earls and Russell but I do not have there Part number handy.

Tom

Re: TH350 Inlet/Outlet
 

I just ordered up fittings for my TH350 a couple weeks back. The thread on my case (1977) was not 1/4" NPT but actually 1/4" NPS which is a straight pipe thread. ATI makes the fittings to go to -6 or -8 AN fittings.
The part number for the -6 is 925137, I ordered mine through Jegs but you could also order direct from ATI.
Thanks,
Chad

Re: TH350 Inlet/Outlet
 

This is true. Do not use pipe (NPT) thread.....

Re: TH350 Inlet/Outlet
 

My trans is an early 70's model is there a possibility they wet to a 1/4 NPT to a 1/4 NPS when they changed over to metric fasteners? My intent is to use a Jiffy-Tite quick connect at the trans both inlet and outlet.

Re: TH350 Inlet/Outlet
 

njk53,
I installed the ATI fittings last night in my TH350 case and they work perfectly. NPS is not metric it is "National Pipe Straight" which is a thread that is typically used on low pressure hydraulic systems. In the ATI catalog they show these fittings on the page for the TH400, but not the 350 but they work fine. Another note, if you order the Jiffy Tite (repackaged as Russell) fittings through Jegs their pictures on the website are misleading showing both halves when you have to order each individually. My male fittings arrived Friday, so I had to go out and order the mating ends as well.
Thanks,
Chad