question on transmission line cooler hose

[spstan]

Does anyone know the pressure of the fluid in a transmission line cooler hose under operating conditions (in psi)? Reason is I'm trying to patch a transmission line in my 1975 New Yorker with 727 transmission. I'm debating on whether to use a cooler hose with 2 clamps on each end or a steel line patch with compression union on each end.

Also what is best way to find the leak? I'm thinking driving for a little bit and placing cardboard under lines to find the drips. Paul

 

[413]

Cooler pressure is quoted as 5-30psi in the shop manual. It will leak immediately on start up so don't go drive, it will just spread all over in bigger area.

Clean and wrap the line with a paper towel and the leak will show itself quickly.

 

[Sixpactogo]

I don't know what the running pressure is on the cooler lines but it is not high pressure that would blow a hose clamp off IMO. As far as a 727, they do tend to leak in a few places. One of the most popular places is at the kick down linkage lever. The best way to find the leak is to clean all the oil off as best you can then after a few hours you should be able to locate if it is above the pan gasket. Good Luck.

 

[1970FuryConv]

Does anyone know the pressure of the fluid in a transmission line cooler hose under operating conditions (in psi)? Reason is I'm trying to patch a transmission line in my 1975 New Yorker with 727 transmission. I'm debating on whether to use a cooler hose with 2 clamps on each end or a steel line patch with compression union on each end.

Also what is best way to find the leak? I'm thinking driving for a little bit and placing cardboard under lines to find the drips. Paul

I have used transmission oil cooler hose and clamps, but only after I flared the ends of the line on both sides of the area that I cut out. Without flaring the ends of the lines, you will continue to have a leak.
Also, if the hose will be near an exhaust pipe, I would use a heat shielding wrap or use steel line and compression fittings. Another option is to cut the original line farther from the exhaust and bend new line for the side of the line that needs to be extended.

 

[57fury440]

I have used rubber hose and clamps to fix a broken torqueflite transmission line. I had one in place for ten years and never had a leak. it was in the front where it came out of the radiator. I finally replaced it so it would look original. I never flared the ends either. If I had a line that leaked because it had rotted holes in it, I would replace the whole thing with new metal lines.

 

[D Cluley]

I used hose for a while, and didn't flare the metal lines, but did use 2 clamps a couple of inches apart.

 

[67_300_Convertible]

A trick I learned from Hot Rod magazine years ago was to use two clamps but to put the screws on the clamps 180 degrees apart on the hose for more even clamping pressure. May or may not be true, but I did it on an aftermarket trans cooler with rubber lines that I installed on my 1969 Pontiac Catalina and never had a leak. If you are going to use two clamps, why not do it this way?

 

[68PK21 440.6bbl]

I installed a aftermarket add on transmission cooler with the lame supplied little fabric in it X pattern type gas line hose, it blew out (split) at over 100+ mph and sprayed ATF all over my windshield at that speed.
Use good hose as I suspect at high speeds the pressure can get very high. I change the hose out to a high pressure many layer fabric AeroQuip hose, problem solved. (in many other applications too)

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