5r55w Line Pressure | Ford Explorer Forums - Serious Explorations

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5r55w Line Pressure


New Member
June 10, 2021
Reaction score
City, State
Gillsville, Georgia
Year, Model & Trim Level
2002 Mountaineer 4.0l 2WD
Vehicle: 02 Mountaineer 4.0l 2WD.

When I start the vehicle the line pressure reads 90-95 psi at around 800 rpm and it will remain steady until I put it into any forward or reverse gear. It engages like it should without being harsh and then the pressure starts to drop and ends up between 4-8 psi. I can increase the rpm and the bands will grab again, then the pressure drops as before. If I put it into N or P and increase the rpm, the line pressure will rise to 230psi-260psi with whining from the pump and then drop down to 0 psi.

What I have done so far:

Dropped pan and replaced filter
Removed and cleaned valve body - no debris found
New seperator plate gaskets
Ohmed out solenoid pack - passed
Energized solenoid pack - audible actuation heard
Ohmed solenoid pack through wiring harness - passed
Checked voltage on pin 3 of harness at transmission - passed
Removed reverse servo housing, cleaned valve and replaced o-ring (old style)
Installed o-ring style IM and OD servo
Flushed cooler

If the line pressure will climb to 260 psi and drop to 0, would this point to the pressure control valve in the pump?

Thanks everyone for any help keeping the hair that I have left.....