Transmission lines are leaking 2007 Ford F150 5.4L v8 2wd

1997 Ford F150

A week ago I got my rebuilt transmission back from Monster Transmissions and finally got the bastard in and now its leaking transmission fluid from both coolant lines going into transmission. I have tried flaring new lines myself, but no luck…still leaking. Wtf could be going on? It wasn’t doing this pre-rebuilt. Thanks in advance

Make sure the lines are being inserted into the mounting inserts. If they are missing they will need to be replaced. If this are attached with quick disconnect lines, the plastic inserts may need to be replaced along with an o-ring seal. Did you have to use the Quick Disconnect tool 307-441 shown below?

The Motor Manual

Trans Oil Cooler Line, Replace


1.Disconnect vehicle ground cable from battery. Record customer preset settings. Record radio anti-theft code if required.
2.Lift and support vehicle using a suitable lift.
3.Disconnect fluid cooler tube from any retainers.
4.Remove any fasteners retaining tube routing brackets, if equipped.
5.Place a suitable container under trans end of cooler lines.
6.Disconnect each fluid cooler tube from trans, as required.
7.Let fluid drain into container until fluid drips slowly from tube.
8.Plug ends of tubes and trans ports to prevent excess leakage.
9.Place suitable container under cooler end of cooler lines.
10.Disconnect each fluid cooler tube from cooler, as required.
11.Let fluid drain into container until fluid drips slowly from tube and cooler.
12.Visually inspect cooler lines from cooler to trans for any components that may hinder removal of lines. Remove or move aside any components that will hinder removal.
13.Remove trans cooler lines.
14.Reverse procedure to install, note following:
a.Fill transmission to correct level with clean automatic transmission fluid.
b.Inspect for leaks, correct any found.

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