Ford Repair: 1990 Ford Thunderbird, torque converter clutch, ford thunderbird

Question
I have a 1990 ford thunderbird LX, no SC. I am trying to figure out what's wrong with my over drive system. It will engage in lower speeds (45-50 mph)and when I get to cruising speed (65-70) and I take my foot off the gas just a little, OD disengages back to drive, and the only way to get it to engage again is to slow back down to 45 MPH. I have replaced the speed sensor, I have adjusted the Throttle control. I can't figure out if it's a sensor or vaccum problem or the Over drive band in the tranny itself, it seems to not work at all after the car has been running for an estimate of 10 miles, any direction in what to check would be great. The gears do not slip either, smoothe shifting.oh, it has 172,000 miles on it, bought it used.Thanks in advance.


Answer
Hello and thanks for the question...I'll try to help.
It sounds like the torque converter clutch is slipping and will need to be replaced. To verify this I would suggest that you bring it to a transmission shop OR the local Ford dealership and have them check it out.
Hope this helps,
Erik