My 99 Taurus works OK if the temperature gauge is in cold position, when the gauge reach the middle or normal temperature the transmision start to slip from first gear to second. If I run the car under 35 mph the car will mantain a low temperaure and wont fail. If I acelerate for a short time temperature reach the normal position and then the transmision fails. Is this an easy fix or I'm talking big $$$ troubble? Thaks

 

Smell your transmission fluid. If it smells burnt you need to rebuild the transmission. Ditto if the color of the fluid is not cherry red.

 

The transmision was rebuild a year ago, do I have to rebuild again? Thanks

 

Its possible the trans is slipping from low fluid pressure...but unlikely. Pump might be going out...but this would cause multiple gear slip..filter could be plugged...but this is bad also..

Transmissions that start slipping when they warm up usually indicate a soft part problem or possibly a worn clutch pack. A lip seal and other semi-rubber component gets more flexible when they get warm and can leak fluid pressure. If its only slipping in second, then I would guess its an intermediate clutch pack lip seal. If you downshift from drive into manual 2nd at around 30-35 MPH...does it freewheel? or does the second gear grab firmly as it should??

drop the pan ASAP and check for clutch material. If there is none, then you can get away with a soft rebuild....

Just a comment....these trannys (AXOD) are one of the worst pieces of crap ford ever came out with...unlike thier rear wheel drive units...the amount of labor to repair them is insane....not to mention the cost of the hard parts.....

good luck