The transmission on my 2000 Nissan Xterra with 114,000 miles randomly started slipping one day. It does seem to be slipping somewhat in all gears, but it's most prominent in 2nd and 3rd. If I keep holding down the pedal, the RPM's keep increasing while the speed is only increasing slightly. Eventually, I have to lay off the gas pedal slightly, and if I manage the gas pedal just right, somehow that allows it to upshift into the correct gear. It's useable, but annoying.

I brought it to my mechanic who is usually trustworthy. He looks at it for 20 minutes, and then claims "it's blown....needs to be rebuilt". Transmission fluid is fine, no leaks that I can find.

As I was driving home from the mechanic in a sad state, I hardly even realized that my transmission had been giving me basically NO issues at all. It was like all of sudden better...shifting into and out of any gear easily. I should mention that the mechanic that looked at it is not a specialist in transmissions. I have an appointment with a specialist coming up. I haven't driven it enough since that day to determine if the transmission is still fine or acting up again.

I have 5 codes which I will reproduce here: P0731 Gear 1 Incorrect Ratio P0732 Gear 2 Incorrect Ratio P1705 Transmission Range Sensor P0120 Throttle/Pedal Position Sensor 'A' Circuit P0510 Closed Throttle Position Switch Malfunction

The only other issue with this car is that it doesn't start occasionally due to what I believe is a faulty automatic transmission switch. I have to pull the shifter towards me as far as I can while it's in park and then it starts. Related to one of those sensors mentioned above?

No grinding sounds or other weird sounds that I can hear. Other than the transmission thing, car seems perfectly fine. Any help would be much appreciated.

  • If you clear all of the codes, do they come back?
    – HandyHowie
    Jan 14 at 10:13
  • 1
    I haven't tried clearing the codes, but I'll give it a shot and take it for a drive to see if they come back. Thanks Jan 15 at 17:36
  • Ok, good to know about the wires/wiring harness or ECU being a possible cause. The wires/wiring harness I guess I could probably do, right? But the ECU would have to be handled by the specialist, no? Jan 15 at 17:40

1 Answer 1


It doesn't need a rebuild. A tranny shifting that badly due to mechanical problems would never correct itself for a time.

A more likely cause is faulty/damaged/corroded wires or wiring harness. An ailing ECU is another possibility.


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