4L60E hydraulic pipes washers or no washers

[seza]

As ever this is a great forum - a big thank you to all those that make it possible,

my 4l60e on a 1994 Burban K1500 been rebuilt recently, running perfectly fine after the rebuild,
but suddenly it developed a major fluid leak inbetween the actual pipe and the bolt that hold it onto the tranny
we are not sure if the hydraulic pipes to/from radiator need washers/O-rings at the tranny end inside where
the pipe flange go [see pic]
my brother who disconnected the pipes initially rekon there were NO washers

your quick reply will be greatly appreciated

 

[Schurkey]

"Hydraulic pipes". Most everyone calls 'em "transmission cooler tubes".

For the record, "pipes" are measured by inside diameter. A half-inch pipe has a half-inch fluid passage or close to it. "Tubes" are measured by outside diameter. A 5/16 tube--like most trans cooler tubes--is 5/16 on the outside, the fluid passage is smaller by the thickness of the tube wall.

No washers. Seals on the inverted taper. The tube should be double-flared seamless steel, secured to the inverted-flare adapter with a tube nut. (There are no "bolts")

Cracked flares are somewhat common.

Aftermarket stainless steel tubes are hard, don't conform well. THEY can be tough to seal. There is such a thing as copper sealing washers. They're not common. I've never seen them, but I've heard they exist from folks I trust.

 

[seza]

Many thanks - Schurkey for the comprehensive reply,
"you learn new thing every day" as they say - never knew that about the dif between pipes n tubes!