New member here looking for a little help with my 93 Merc Grand Maquis' AODE tranny.
The tranny is experiencing a very intermittant problem where the torque converter lock-up clutch wants to engage then disengage when the tranny is in 3rd gear. It is most noticable around the 35-39 mph range with light throttle pressure. You can feel the car "surging" and hear the enging rpm rising and then lowering as the converter locks and unlocks. As soon as the tranny shifts into 4th gear the converter instantly locks up with absolutely no problems in 4th at all! Again this whole 3rd gear issue is very intermaittant and only happens about every 250 miles or so, and will only do it for about a days worth of driving and then straightens itself out and operates flawlessly for another 250 miles or so. The tranny is original to the car with 107,000 mi on it. The tranny did get regular fluid and filter changes just about every year of its life, and I have the service records to show for it. When I first bought the car, I changed the tranny fluid and filter myself (including draining the converter), and was amazed at how clean the inside of the tranny looked. I am also 99.99% sure that the converter has been changed at some point also because its painted a nice shade of blue, and I don't think Ford ever painted their converters from the factory. I refilled the tranny with Merc V. I have also replaced the converter lock-up solenoid, as well as the throttle positions sensor. Anyone have any ideas? Maybe so dirt or debris moving around in the valve body? Please help.
Thanks

 

tsb 96-25-97
Torque converter clutch shudder or vibration may occur under light to moderate acceleration above 56 km/h (35 mph) while in 3rd or 4th gear or on 3-4/4-3 shifts. This condition may be more noticeable on higher mileage vehicles (24,000+ km (15,000+ mi)) when the torque converter clutch engages or disengages on light to moderate acceleration.
ACTION:[/u]
Perform normal diagnostics and change the transmission fluid. Changing the transmission fluid should reduce the possibility of shudder/vibration. Refer to the following Service Procedure for details.
I think your right about somthing in the vavle body , when you have the fluid and the filter changed was it a flush or a drain and refill . I would suggest you have it put it on a flush machine .