Mercury Mountaineer transmission gear slipping with issues in 2nd gear and failure to engage reverse on Mercury Mountaineer

Some Mercury Mountaineer owners report experiencing transmission gear slipping issues, particularly in 2nd gear, which can stem from factors like transmission fluid problems, torque converter clutch application issues, or internal component failures. These owners may also notice a lack of power after the 1-2 shift, potentially indicating un-commanded torque converter clutch application, which could trigger diagnostic trouble codes such as P0742 and/or P1742. Additionally, some owners report a failure to engage reverse, often attributed to transmission fluid issues, solenoid malfunctions, or valve body problems. These gear shifting difficulties can frequently be resolved with straightforward fixes. It is advisable for owners to have their transmissions thoroughly inspected by a qualified mechanic to identify the specific causes and consider overhauling the transmission if necessary. Furthermore, they should avoid flushing the transmission fluid if there are concerns about sediment entering solenoids, as this could worsen the situation.