I am new to the forum so hello everyone.

The trouble I am having with the Montero Sport is that I had the entire transmission rebuilt and it is shift flaring from 2nd to 3rd and banging gears ( 3rd to 2nd) when downshifting to stop. Before I took my car to the tranny shop, I took the car to the dealer. The dealer replaced the valve body (1600$) but the problem continued. I then decided to take my car to a mechanic who had already repaired my eclipse spyder's transmission that works perfectly. Before I had the Montero Sport tranny rebuilt, it had the same problem with the shift flaring but not the banging gears. This car has 60000 miles on it and it is a 2000 Montero Sport with a 3.5L Limited 4x4 automatic. I had the mechanic take down the tranny after the rebuild two times and he replaced the valve body twice as well. He also checked the disks and they were good. The tranny was rebuilt with OEM parts. I heard that the ECU might have something to do with this problem but when I tried to have it rebuilt it tested fine by the ECU rebuilders. I have no idea what to do. Whether I get a new ECU with immobilizer from the dealer which is around 700 $ total or a new tranny for about 2500$ plus installation, the problem is going to cost me alot of money. I really love this car and do not want to get rid of it. Recently my mechanic had another Montero Sport with tranny problems and when he rebuilt that car, it too has the same problems as mine. My mechanic nor I have any idea whats going on. I then took my car to the dealer to have a tranny flushed to see if that was it, but the problem continues. Any help or advise is appreciated.