JASPER’s Reverse Servo Cover Update


This support plate, mounted over the reverse servo cover of the Ford 4R55E/5R55E, allows the transmission to maintain reverse in 1995-2008 Ranger, Explorer and Aerostar.

Jasper Engines & Transmissions has made an update to the reverse servo of Ford 4R55E/ 5R55E transmissions produced between 1995 and 2008.

This update centers around the installation of a support plate over the reverse servo cover of 4R55E/5R55E transmissions found in the Ford Ranger Pickup, Explorer SUV and the Aerostar minivan. Drivers noticed the loss of reverse in these vehicles. The problem centered around the reverse servo gasket of the transmissions.

The gasket lays underneath the reverse servo cover. “These OE gaskets handle in excess of 250 psi when in use,” says Craig Leuck, JASPER Transmission Division Manager. “We have found that aftermarket gaskets can hold about 425 psi. But, we also know these transmissions will see pressures in excess of that.”

“JASPER’s Reverse Servo support plate allows the servo to handle in excess of 600 psi, well above what the servo will see, to make sure these transmissions can maintain reverse,” added Leuck.

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