One problem related to transmission not engage has been reported for the 2008 Mercury Mariner. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2008 Mercury Mariner based on all problems reported for the 2008 Mariner.
Driving in traffic, when vehicles transmission disengaged. Depressing the accelerator only revved the engine, but no forward motion. While coasting, managed to get vehicle out of traffic & to a side street. From a stop, vehicle would accelerate, but when shifting into 3rd gear, goes into a "neutral" condition and coasts. Paid Ford dealer to do evaluation, and was told this was a known issue with this vehicle. Was quoted $3000 for the repair.