I have a dangerous problem when I'm in traffic. My car has mileage of 187,000. After it has been driven a while, the transmission jerks and moans when I shift gears (in-between any gear), and even though the engine sounds like it is accelerating, it doesn't move! Very scary in traffic. What causes this?
There are two possibilities. This could be caused by internal wear in the transmission. Fluid level and condition should be checked. If the fluid level is low or smells burnt it may be an indication of an overhaul needing to be performed on the transmission.
Another possibility is oil or fluid contamination in the connectors to the transmission. Oil or fluid contamination can cause the control area network (CAN) system faults which can throw the transmission into failsafe mode. This will often be accompanied by faults in the transmission control unit. Reading out faults and unclipping and inspecting the connectors for oil intrusion need to be carried out. You may want to enlist the help of a mechanic, such as one from YourMechanic, who can read out the faults, diagnose your shifting issue, and recommend the proper course of repair.