I purchased a 2006 Nissan Altima SL 3.5l 5 speed automatic. The car needed a motor. Owner stated the transmission was fine. I replaced the motor. I had no reverse. Forward gears, but no reverse. I purchased another transmission (rebuilt??) and installed it. The same condition. Forward gears but no reverse. I used the same torque converter, nuetral safety switch and fluid cooler. Everything else came with the transmission. There are no codes present with either transmision? I readjusted the shift cable, I unplugged all the connectors and tried it again. Same problem. I checked the pressure at the reverse test port (specs 60 - 80 psi at idle) and the pressure pegs my 250 psi gauge?? It also has a steady drip out of the front seal (or pump o-ring?). The transmision is not a CVT. It is model AW55-50sn (RE5F22A). I am at a loss on what to do. Is it inside the trans or could it be the TCM which is external on this car (behind the glove box)? Thank You, Chris (retired master tech

  • Does the TCS light come on in reverse? It doesn't seem likely that's the issue. In any case you can disable it using the button on the dash, which may be labeled VDC. If there is no button then your car isn't equipped with traction control.
    – GdD
    Mar 7, 2019 at 9:01
  • 1
    Loss of 4th Gear and/or Reverse: Another common problem is an inoperable fourth or reverse gear. These issues are often caused by design flaws in the Reverse Boost Valve, channel plate, and stripped splines on the 4th gear clutch hub shaft. - from transmissionrepaircostguide.com/aw55-50sn - Could therefore be a fault on both boxes.
    – HandyHowie
    Mar 7, 2019 at 10:13


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