Trans Cooler Problem

[d2dave]

This is doing my head in. I have fitted a new Allisprt cooler as well as an aux cooler.

I wanted to run the engine with the return line disconnected in case there was any manufacturing debris/swarf in any of the two coolers.

According to RAVE the supply to the factory cooler is to the drivers side of the cooler.

So I cut into the return line and ran the out from the factory cooler to the aux and then back to the transmission. See pic.

So here is what I did. Looking at the pic, I disconnected join "A" and fed the return (blue line) into a bucket.

When I started the engine oil was pumped out, all over my shed floor from join "A" but from the transmission red line.

Ok I thought, RAVE got it wrong and it goes the opposite direction. So I rejoined "A" and disconnected line "B" at trans, expecting oil to be pumped out of this line.

Nope, the oil was pumped straight out of the auto at "B". I connected "B" and retried what happened first time, with the same result, oil being pumped out red line from trans.

I then disconnected "B" again and blew compressed air into line at "B" to make sure there was no blockage in any of the coolers. A large amount of oil was blown from from blue line at "A"

So regardless of which line I disconnect from transmission, they both pumped oil. What have I missed here?

185634

[AK83]

did you physically cut the lines and join using hose clamps?

From my understanding of what many here have written on the subject, hose clamping is not durable to hold back the high pressure that the ZF box produces.

If you read what most of the folks have done, they generally use screw type connections (eg. -AN fittings) for the connections to and from any new hardware.

[ross_coupland]

Could you maybe disconnect the lines at the transmission end, to confirm which is the output connector, and go from there.

[jwb]

Did you get this sorted?
The system is normally under pressure, I wonder if with the open circuit at point A the fluid is somehow just finding the path of least resistance and coming out the 'return'.
What happens if you have the break at A and block the red line back to the transmission.

[PhilipA]

I am pretty sure that the "hot" side of the cooler is the LH side as this is the side which usually fails including on my car where it was on the way to failing.
Regards PhilipA