Three problems related to automatic transmission torque converter have been reported for the 1998 Mercury Sable. The most recently reported issues are listed below.
The car lost drive power, and appeared to go into neutral. The transmission shop later found that a shaft, from the torque converter to the pump, had snapped. The shaft is a fairly substantial piece of metal. The shop repaired the transmission but could not make a guess as to the reason for the metal failure. I have the shaft that snapped and can provide digital images. There is no obvious reason to me why it would have snapped wether it is design or metallurgy. I can provide digital images of the component breakage. If you so desire, I can provide you with the part if you wish to perform failure analysis for metal defects / manufacturing problems, or design issues. In my case, the failure happened on a lightly travelled road, with no traffic around. If this a failure that had occurred on a busy highway, while turning in traffic, or during many scenarios - this could have caused a real problem for me, passengers, or other motorists. I hope that anyone else with the same failure is as fortunate.
Locked torque converter seems to disengage when going down hill. Also, speed control cannot control speed of car going down any slight hill. Seems to be not locked up, etc. Cannot use engine compression, etc, to slow vehicle. Cruise control us is useless on any type of downgrade! is this a design flaw or can it be repaired? vehicle is a leased car through wheels, inc. Thank you.
The torque converter clutch did not engage at times, which caused a hard shift.