[shorod]

Did you set the parking brake, and is it possible the shops you called were under the impression that the brakes don't hold rather than that the transmission doesn't hold? When in park, the brakes really are out of the circuit except if you use the parking brake. But the parking brake is cable actuated rather than hydraulic (using the brake lines).

Also, does your Mountaineer have all-wheel drive (AWD) or 4-wheel drive (4WD)? Are the rear brakes drum or disc? If you have 4WD, the transfer case could have gone into neutral and allowed the vehicle to roll. I'm not sure if the AWD center differential/transfer case would be able to allow this or not. If you have rear disc brakes, the parking brake is a drum setup located within the rotor and completely separate from the normal hydraulic braking system.

If you have rear drum brakes, then the same shoes are used for the parking brake as the normal hydraulic brakes. They are still cable actuated, but that might explain what the shops are talking about with a "screw adjustment thing." Drum brakes use a threaded self adjuster to spread the brake shoes out to just before they make contact with the drum. If the adjuster is backed off too far, the parking brake will not be able to move the shoes far enough to hold the vehicle on an incline should the transmission/transfer case also fail to hold the vehicle stationary.

Were you able to start your Mountaineer up and drive it back into your driveway after this? Does it seem to hold on the incline?

-Rod