Transmission problem, suspecting electronics??

[eric5]

Hi everyone. i am new on this site and i want to ask advice for my 2003 nissan pathfinder!
This is the story. my car got flooded up to approx the radio level, so i changed all the electronics (ecm, transfer case module, auto trans module, air bag module, g sensor for abs, all these parts were from wreckers model 99 to 2004) I have also cleaned all the connectors with an electronic cleaner!
There is no more error lights on the instrument panel and no more error codes.
The engine runs perfect now.
Have not done any relearn/reprogramming, i just unpluged the battery for 30min and then drove the car for 30 min on the highway.
The transmission was slipping, the gears were not engaging properly, high rpms and after a few tests the 4th gear would not engage at all! (no error lights came on)
I had a mecanic fit a second hand trans 130,000km, then i picked it up 4 days later & same problem! gears are not engaging, slipping, high rpms. after a few road tests, no 4th gear again (still no error light came on )
The mecanic did not find any error codes either & when i tried the self diagnostic for tcm nothing comes up!
The mecanic is going to fit another transmission in about 10 days but i am scared that it's not a transmission issue but maybe a sensor or computer or a short or maybe an electronic problem or god knows.??!!
If anybody can help, your advice would be hugely appreciated!
Thanks.

[Towncivilian]

Welcome to NICO!

Are you sure your check engine light is not burnt out? With the ignition set to "ON", it should light up.

How is the transmission fluid condition and level? Check it properly by following these instructions:

1. Drive around for 10 minutes in the city after the transmission is at operating temperature.
2. Park on a level surface and apply the parking brake.
3. With P selected, shift through every gear and return to P.
4. Pull the transmission dipstick with the engine idling, wipe it clean, reinsert it completely, and read the level. It must be within the notched area labeled "HOT". Check for fluid contamination after wiping on a paper towel.



The fluid should be red, and not smell burnt.

What was the part number used for the transmission control module? If it is the incorrect part (too early a TCM, perhaps one used for the non-HD version of the RE4R01A trans that came with 01+ Pathfinders) it may be causing your issues.

[WDRacing]

That's exactly what I was going to say. Either the fluid type is wrong or it's low/dirty or the TCM is the wrong part number.

[eric5]

Hi guys thanks for the replies
I went to check atf,its black ,smells like it s burned , and they was about 700 ml of extra fluid .so i empty the 700 ml ,now level is good but no difference in gear change still reaving up to 3500 befor engaging and fills like it s slipping!!
I also chech the parts numbers. On ecu and tcm (old tcm n 31036 3w200/a64-000 x22 3129. New tcm n 31036 3w200/a64-000 x22 4225)(old ecu n 23710 3w201 mecm-w324 a1 3123 new ecu n 23710 3w201 mecm-w324 a1 2208)looks ok???
Let me know what u guys think !!
Thancks a lot
Eric

[eric5]

Sorry forgot about the engine light ,it lights up when i turn the ignition on so its ok!!
Eric

[Towncivilian]

Could you provide your VIN? It will help me verify ECM and TCM part numbers.

Black transmission fluid is not good. Do you know what fluid your mechanic used? You should do a complete fluid exchange. You can find instructions in the general information thread linked in my signature. Castrol Transmax Import is a good fluid, I recommend it if you can obtain it.

[WDRacing]

That fluid is completely spent. Which also makes me think you're filter will be very clogged as well. Dirty fluid wreaks havoc on all the check valves and solenoids inside the transmission.

Change your fluid and filter ASAP. Don't just do a flush, make sure the pan is dropped, cleaned and the filter is changed. Should cost about $350 at your local Firestone or Brakemax etc. I wouldn't go to the stealership for this, they are outrageous for labor.

[Towncivilian]

There is a superb how-to guide on dropping the pan and changing the in-pan strainer here. Do note that the strainer does not filter very finely and if it is clogged or has caught any significant amount of stuff, your transmission is almost certainly doomed.

The ECM and TCM part numbers look correct. Your problems are being caused by the fluid, and the fluid is black because it has either been exposed to very high temperatures for an extended period of time or it is full of clutch wear material. It wouldn't surprise me if both cases were true. Where did your mechanic find such an awful used transmission? Did he use a 2001 model year or newer transmission? If he used a 1996-2000 transmission, those are not the heavy-duty variant of the RE4R01A and they will not handle the additional power of the VQ35DE well at all.

[WDRacing]

Not only that, but how does one not put new fluid into a used trans? Fluid doesn't turn black over night, usually it takes 30,000 miles or so.

[Towncivilian]

Exactly my thoughts. I would consider searching for a different mechanic, this guy doesn't seem to care from where he sources his parts.

[eric5]

Hi guys
Thanks you for your help!
The mecanic told me that they did not replace atf fluid only top it up.
I am stuck with that mecanic because the job is under 3 months warranty.
He s looking for a other transmission.
What i am worried about is that the problem is not the transmission but a short/electonic/sensor...
Because after the flood and all electronics replaced the first transmission acted the same (coincidence?) started with bad gear engaging then no 4 gear ,changed atf twice (just by draining the pan) cleaned filter(in pan)and woud be black in just a few road test.
Exacly the same with the second transmission that is why i am suspicious of the electronique!
The second trans is a 2001.
I have tryed tcm self diagnostic with repair manual from your web site.
And no code light comes on.

SAT717K PNP switch, overdrive control switch or throttle position switch
circuit is disconnected or TCM is damaged.
⇒ Go to TCM Self-diagnosis Does Not Activate (PNP, OVERDRIVE CONTROL AND THROTTLE POSITION SWITCHES CIRCUIT CHECKS), AT-255.
t1 = 2.5 seconds t2 = 2.0 seconds t3 = 1.0 second t4 = 1.0 second

LC EC
FE
SAT136K
TCM Self-diagnosis Does Not Activate (PNP, Overdrive Control and Throttle Position Switches Circuit Checks)
SYMPTOM:
O/D OFF indicator lamp does not come on in TCM self-diag- nostic procedure even the lamp circuit is good.
DESCRIPTION
NBAT0204S01
P PNP switch
The PNP switch assemble includes a transmission range TF switch. The transmission range switch detects the selector position and sends a signal to the TCM.
P Overdrive control switch
Detects the overdrive control switch position (ON or OFF) and sends a signal to the TCM.
P Throttle position switch AX Consists of a wide open throttle position switch and a closed throttle position switch.
The wide open throttle position switch sends a signal to the SU TCM when the throttle valve is open at least 1/2 of the full throttle position. The closed throttle position switch sends a signal to the TCM when the throttle valve is fully closed. BR
NBAT0204
PD
I have checked pnp and it s good!

I am unable to check overdrive control switch or throttle position switch because the manual is not showing the right connectors layout maybe i have the rongh manual?

This is the manual i find on your web site:
Infinity qx4 model rs50

EDITION: JULY 2002
REVISION: JULY 2003 PUBLICATION NO. SM3E-1J50U2
QUICK REFERENCE INDEX
All rights reserved. No part of this Service Manual may be reproduced or stored in a retrieval system, or transmitted in any form, or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior written permission of Nissan Motor Company Ltd., Tokyo, Japan.

Coud you please send me the right conectors layout and procedure for trouble diagnostic over drive and throttle position !!

My vin number is :jn1vawr50a0151498
Let me know what you guys think?
Taking the car to a pro woud probably be the best way but i cannot aford it after the transmission cost!
Thanks again .
Eric