Damage Inc.

iTrader: (7)

I'm trying to replace my tranny cooler lines from my 4l60e with braided 6an fittings. I need to know what thread is in the case of the trans that the hard lines connect to. Obviously I'll have to replace the OEM housing fitting, but I need to know what thread that is to replace it.

It looks like a hydraulic thread? Thanks.

BTL FED

iTrader: (9)

I dont believe that there is no thread, they kinda snap in and have a c-clip to hold them. What I would do it get a couple of those Earl hard line adapters, and leave about 3-4 inches of the hardlines attached to the tranny, and put those adaptors on right there

Spl170s

iTrader: (8)

i think he is talking about removing the couplers in the transmission and replacing them. needs to know the size of the threads in the actual case itself at that point.

Ru2slo_99

The threads on a TH-350 are 1/4". Just pull one of those out and go by your local speed shop to compare the threads.

under_construction

iTrader: (1)

They are 1/4 NPT - a 1/4NPT to 6AN straight adapter works great, then use a 45-90 degree hose end, this will allow you lots of positioning options.

Spl170s

iTrader: (8)

so on a TH400 it would be a 1/4 npt thread as well i the case?

i was about to ask this in a new thread...thinking of running braided line also to get rid of the stock lines...

not trying to hijack the thread on ya also!

thanks

Damage Inc.

iTrader: (7)

I talked to a speed shop and told him that the threads should be the same as a TH400, but he said they were not and gave me a shitty look. He said he has nothing to offer me. I'm going to have to ask a hydraulic shop or something to see if it's a special thread. It looks like a 13M, but I'm not sure.

I would retain some of the hard line, but my mechanice cut them and threw them out because he was set on using stainless line. $$$

White98Z

iTrader: (3)

Well i pull those plugs out of my 4l60e they swap right over to my TH350 That is was a lot of people do so they can still use the factory clip style lines.

Spl170s

iTrader: (8)

i was afraid to bent my stock lines to fit up with the TH400 location. they don't seem to be in the same area....looked like the lines had to bend alot to get there...... i wanted to use the stock plugs over into the th400 till i saw this.

how far away is it from working then?

White98Z

iTrader: (3)

I dont know about on on a th400 but i have seen many people just bend them tell thay fit then you can bend them more to look nice.

James B.

iTrader: (1)

Lines are forgiving. I bent mine all over the place.
Sometimes making the connection requires some Disney® Engineering.

http://bertok.us/pics/80swap/80lines.jpg
http://bertok.us/pics/80swap/60lines.jpg

Damage Inc.

iTrader: (7)

We tried a 1/4 NPT, didn't work. That's not the right size. Hopefully this custom hydraulic thread will come thorough for us.

Jimmy P

iTrader: (177)

Any update on this?
I want to run a braided lines to my th400, but just wondering what thread to get?. One guy swears on his life its a 1/4 NPT, then someone else says he tryed that and didn't work.
How easy is it to remove the oem housing fittings on the trans case?

James B.

iTrader: (1)

This is a picture of a the Quick Disconnect fitting used on inlet and outlet of the 4L6X-E and the outlet of the 4L80-E. It is pictured next to a 1/4" NPT brass nipple:



These threads are 1/4" straight.

I am working on a Demolition Derby car right now, 1979 Cadillac Sedan DeVille with a 425 and a TH400. I rebuilt the TH400 last weekend and will be reinstalling it tomorrow. One of the things on tomorrow's list of chores is to bypass the cooler circuit and run the "out" right back into the "in".
I will post my findings with the TH400 cooler line fittings.
-James

James B.

iTrader: (1)

Got the TH400 installed in the Caddy today. On the TH400 the threads are tapered 1/4".

ls1408cp

iTrader: (37)

http://www.tciauto.com/tech_info/cooler_fittings.htm
this might help

Jimmy P

iTrader: (177)

James,
How easy is it to remove those stock fittings? So basically you just remove those, then a 1/4NPT to 6AN straight adapter, and your good to go right?
thanks

James B.

iTrader: (1)

On the newer transmissions they are threadlocked to the case. Put a closed-end wrench around them and get some leverage. The QD fittings are steel and will not break off.

On the older transmissions they come out much easier. They had something that more resembled thread sealant rather than thread lock.

I've never had a problem removing either.

1/4" NPT to -6 AN.... Yes!

1976CamaroGuy

iTrader: (8)

I realize this is an old post, but I found this thread searching for examples of braided lines and wanted to point to something out in case someone else stumbles on this via a search. Especially if they type in "what size fitting for transmission case"

The thread the transmission case is 1/4 as you pointed out, but it's not 1/4 NPT....it's 1/4 NPSM

The difference? 1/4 NPT has tapered threads and 1/4 NPSM has straight threads. This is apparent in your picture that you posted.

You can actually run a risk of cracking the tranny case driving a tapred NPT thread into it.

Just wanted to point that out and carry on

mrvedit

I just used a AN-6 Male to Male adapter and threw an O-Ring on it. It does not leak.
(The fitting on the lower right is the factory fitting for comparison purposes.)