This is a 94 965 w/aw30/40 tranny. I noticed a whine under the car a month ago and it would go away after driving a short time. I thought it was a pulley bearing making the sound. I then tried to tow an open u-haul trailer and by 30 miles I could smell burned trans fluid and the tranny began to slip and shudder. This trans has 188,000 and was recently flushed by machine at about 185,000 with BG brand synthetic fluid. When I checked the fluid level hot several times to confirm the level, it showed two to three inches above the hot marking. I checked the level after shifting through all gears for 5 seconds and then waiting one minute before checking.
Once I got the vehicle home and waited until the next day I checked the level cold finding the level still well above the hot mark. My neighbor who is a toyota and mercedes tech/instructor says that too much fluid is bad for an auto tranny. I recently did a home flush with standard dexron/mercon III and all is well. Does anyone have details about having too much tranny fluid?

Thank you.
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92 244 lowered, Bilsteins, IPD sways, Unitek cam/header, TSW Revo 18x8's - 94 965 , 96 964. - 76 Datsun 280Z lowered, modified head, cam, headers, intake