94 Max Automatic Trans Problem

[maximamann]

My 94 maxima has 142K miles on it and it's starting to have trans problems. There's a slight overspeed from 1st to 2nd gear and then the torque converter doesn't want to lock up once it's in OD. I know this because when in OD, you can romp down on the accelator and the RPMs will clime to 3K to 4K with only slight/sluggish acceleration. Sometimes you can let off the accesator and let the car cost down to about 35-40 and then ease back on the accelator and it'll (torque converter) will lock up and you can go on. I've had the car in the shop and the mechanic said I only have 90 lbs of pressure where there should be 200. By the way, I've flushed the fluid already with only a slight improvement in operability. Any suggestions?

[cyeed]

I have the exact problem with my 93 automatic Maxima. Additionally, mine won't go into reverse gear. Since mine happened so sudden, I don't want to be quick to blame the transmission. I would like to think there is some other mechanical failure other than the transmission. I changed out the CV axles a few months back, and wonder if that had anything to do with this!!

[maximamann]

Sorry to hear you have the same problem. I don't know if mine was sudden or not. This is the car my daughter drives and she's away at college. I only get called when it's really bad so there's no telling how long this has gone on.

At any rate, I found a transmission test on the web, I think at maxima.org or some link off that page. It has you put your trans in park, turn the car on two or three times, move the lever from park to different positions and then count the number of times the transmission power light blinks. Supposedly that polls the computer and tells you if it has a trans error code. Since yours was sudden, maybe that will help. I tried to find the test on my computer but couldn't. If I run across it, I'll link it to the message.

PS - I've flushed the fluid in mine but if that helped at all, it was only marginal. If you find some majic bullet, please share it with me. Thanks.

[cyeed]

I have called several transmission shops, and also the dealer. They all agree that flushing won't heal the car, and some say it might make it worst. Based on the symptoms, i.e., not having reverse gear, second gear, or 4th gear (therefore no Overdrive, the rpm revs up in O/D on, and the car goes nowhere), one transmission shop told me that it could be a bad transmission band, but then that won't fix not going into reverse. Looks like internal transmission problem, requiring swapping out with a junk yard one, or rebuilding. I ran diagnosis on the ECU, and no fault codes appeared. I do not know what this transmission test is, but if you do find it, I would certainly like to run it. Thanks for responding.

[maximamann]

found it (finally):

how to run the self-diagnostics test on your auto tranny:

1. Start engine and warm it up to normal engine operating temperature.
2. Turn ign switch to "OFF"
3. Set A/T mode switch to "AUTO"
4. Set O/D switch to "ON"
5. Move selector lever to "P" position
6. Turn ign switch "ON" (do not start engine)
7. Power indicator lamp should come on for about 2 seconds
Then:

1. Move selector lever to "D" while depressing brake pedal
2. Turn ign switch "OFF"
3. Set O/D switch to "OFF"
4. Turn ign switch to "ON" (do not start engine)
5. Move selector lever to "2" position
6. Set O/D switch to "ON"
7. Move selector lever to "1"
8. Set O/D switch to "OFF"
9. Depress accelerator pedal fully and release it
10. Check power indicator lamp

Codes:
There should be a longer start signal followed by 10 shorter signals, note which of the 10 short signals is longest
All flickers the same: self-diag OK
1st flicker is longer than others: revolution sensor circuit
2nd flicker is longer: vehicle speed sensor sensor circuit
3rd flicker is longer: throttle position sensor circuit
4th flicker is longer: shift solenoid valve A circuit
5th flicker is longer: shift solenoid valve B circuit
6th flicker is longer: timing solenoid valve circuit for non limited slip tranny(89-94GXE); overrun clutch solenoid valve circuit for limited slip tranny (some, maybe all auto 92-94SE)
7th flicker is longer: torque converter clutch solenoid valve circuit
8th flicker is longer: fluid temperature sensor and A/T control unit power source circuit
9th flicker is longer: engine speed signal circuit
10th flicker is longer: line pressure solenoid valve circuit
lamp does not come on: inhibitor switch, overdrive switch, and throttle position switch circuit
__________________

[cyeed]

Thank you Maximamann. I have searched the inside under the dash, and I can not find the A/T control unit. Do you know where I can find the unit? I have also searched this web site, but no mention of the location. My Haynes repair manual doesn't mention it either. Any help is greatly appreciated. I am anxious to run the test. Thanks in advance.

[maximamann]

Originally Posted by cyeed

Thank you Maximamann. I have searched the inside under the dash, and I can not find the A/T control unit. Do you know where I can find the unit? I have also searched this web site, but no mention of the location. My Haynes repair manual doesn't mention it either. Any help is greatly appreciated. I am anxious to run the test. Thanks in advance.

Sorry, but I don't know what an AT control unit is much less where it is either. Sorry I'm late responding but we've been on OT at work.

[cyeed]

Originally Posted by maximamann

Sorry, but I don't know what an AT control unit is much less where it is either. Sorry I'm late responding but we've been on OT at work.

In your post about the transmission test, what are you referring to when you say put the A/T switch in Auto. I guess I assumed you were referring to a A/T control unit similar to the ECU. Unless it's something which your 1994 Maxima has and my 1993 doesn't, which I doubt! Anyway, that's what I need, the location of the A/T switch!!

[nissanmaxima]

Originally Posted by maximamann

found it (finally):

...
3. Set A/T mode switch to "AUTO"
...

Inside of my car (Nissan Max '93) I have a switch that has three positions, Power, Auto and Comfort.

Is this part of step number three? Because I can set it to auto.

Here is an illustration:

P.S. I hope this is it...I know it's not the A/T Control Unit.