My car was stuck in 3rd gear "limp home mode"

[AE75]

Hi,My car was just done the restoration, gearbox was changed to recond units. After the changing, it changed every gear as wish. So i left to recondition of engine area include changed DME, after few month later. The engine was done, and problem again at the gear was stucked in 3rd gear. For this problem i done:1. changed S.E.M switch2. Gear Selector3. Reuse back the valve body4. Frushing the gearbox5. Change back the valve body, & even change another valve body6. Gearbox filterSo what else you all suspecting? Is anyway to reset the Transmission ECU?For information, my car is E32 with M30B35 engine, the gearbox is 8 pin 4HP-22.