Need Auto Trans Expert.

I have a 90 Max with an auto trans. It is a remanufactured that was put in in 2002, it has 22,000 miles on this one, and it will not move forward or reverse. The car was being driven up a very slight grade when the motor just reved up on the car no longer was moving forward. This is the third trans that has been put in this car since it was new. The car is in to nice of condition to send it to the wrecking yard. I'm unemployed at this time and cannot afford an other trans. I'm capable of removing it and tearing it down by the book if I have to.
I did first run all the dianostics on the A/T control unit and it checks out.
I checked all the connectors that where listed in the dianostic procedures.
What could it be????

I know exactly what it is: Nissan's automatic transmissions are dogshit.

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What could it be????

No. Nissan autotranny works like dream. Electrical wirings are skinny; if they are conditioned as they should, all is well.


molhannah:
Did u check the tranny/groundings/harness PM pages??????????????

click: http://www.cardomain.com/memberpage/748507/1




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I checked all the plugs and circuits. I went thru 20 pages of trouble shooting and self diagnoses. I checked all electical conponents at the A/T control unit that I can except the one you check while driving, because it won't drive. No where in the trouble shooting section does it say car won't move in any gear. Out of all the test, the only one that didn't have the right voltage reading was wire # 14(idle switch) Is there any electrical item that would make the just sit in all the gears????

I checked all the plugs and circuits. I went thru 20 pages of trouble shooting and self diagnoses. I checked all electical conponents at the A/T control unit that I can except the one you check while driving, because it won't drive. No where in the trouble shooting section does it say car won't move in any gear. Out of all the test, the only one that didn't have the right voltage reading was wire # 14(idle switch) Is there any electrical item that would make the just sit in all the gears????

Dunno what is this wire # 14...

If solenoids do not get power, they will not activate mechanical tranny valves. Check coil resistances on the tranny connectoras illustrated. Check that TCU gives +12V to the TCU side of this connector. If all is here ok, then its on mechanical side: pressure missing or smtg else...


Edit: TCU pin 1 is for "Line pressure valve" solenoid. The same pin number is on the tranny 8-pin connector. Measure 1.5-2.5V engine warm, ign ON. Then press gas pedal: Measure less than 0.5V engine warm, ign ON. ...just like is illustreted on my web page.


Check tranny pressure line. If no pressure, car does not move. Mech problem, dunno ...swap tranny.
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Finally back again: Ok #14 wire is pin #14 on the ATC box goes to throttle black box. It doesn't read like the book says.
Checked pin #1 @ solenoid harness from trany and found 7.7 ohms, book says 2.5-5.0
Checked voltage from pin #1 of engine harness and found 4.9 volts and no change when moving throttle. Where do I go know?
No I haven't check pressures yet, waiting to get eguiptment from friend. Talked to previous owner about car: He said the had no noise or other signs of any mechanical failures prior to the car just acting like it went into neutral.

Finally back again: Ok #14 wire is pin #14 on the ATC box goes to throttle black box. It doesn't read like the book says.
Checked pin #1 @ solenoid harness from trany and found 7.7 ohms, book says 2.5-5.0
Checked voltage from pin #1 of engine harness and found 4.9 volts and no change when moving throttle....


That is guite high resistance - and its THE line pressure valve. Probably still ok. I would try to find exact answer from somebody who has been playing with this...

How about all the others??? If they also are 3-4ohms above limit, it might be bad common gnd inside tranny. Btw. The solenoid pack may be replaced without taking tranny out.

Check out your TPS from opened TPS connector: linear resistance 1-9kOhm. U can clean and/or open & clean TPS, see my web page.
TCU uses TPS to determine gear change, if that is cut, who knows what TCU decides.

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I have a 90 Max with an auto trans. It is a remanufactured that was put in in 2002, it has 22,000 miles on this one, and it will not move forward or reverse. The car was being driven up a very slight grade when the motor just reved up on the car no longer was moving forward. This is the third trans that has been put in this car since it was new. The car is in to nice of condition to send it to the wrecking yard. I'm unemployed at this time and cannot afford an other trans. I'm capable of removing it and tearing it down by the book if I have to.
I did first run all the dianostics on the A/T control unit and it checks out.
I checked all the connectors that where listed in the dianostic procedures.
What could it be????


Hey, Did you get this Fixed???????

No I haven't. I have tried everything except re-checking all the pressure ports. I have a new job with to many hours and have not gotten back to it in a few weeks. After the pressure checks, if they pass, I will pull it and check the torque converter.