2002 2wd Pathfinder with P0744 SES and shifting issues

[Pathfinder2002]

Everyone,

I'm trying to get my 2002 Pathfinder 2wd Auto to shift correctly.
Here is the problems i'm facing and wonder if I should just swap in a used transmission?

The SUV was maintained well through out it's life with regular oil changes, transmission oil changes with OEM factory filters, OEM Nissan Transmission oil. The last flush and change was about 3 months ago and 8000 miles. Around 140,000 miles now the car started to have shifting issues into D when the car is cold. Then on 3000 mile trip at 143,000 the car has a SES P0744 and shifting from 3rd to 4th around 65 miles the car started to jitter. From all the information i've been reading it's a TCC or clog/broken Solenoid. Can I just trouble shoot the solenoid issue and will that fix my shifting problem? Will replacing the broke or clear the solenoid will resolve my P0744 error code? How can I fix the cold morning shifting issue without rebuilding my transmission? I was told by a mechanic it's best to rebuild or replace the transmission due the fact this transmission is on it's way out the door. Is this true or mechanic up selling my problem.

Please help!
Does anyone have a picture where solenoid 4th gear shifting will be located?

[Pathfinder2002]

Here is a write up for the problem and solution since no one responded with any help.
My Pathfinder pulled a P0744 SES and wasn't shifting into 4 gear jitter at 60-65 miles per hour.
This hesitation was due to dirty transmission fluid and a dying TCC lower solenoid which can be seen once you take out the transmission oil pan.
So I found whole bunch of info on youtube for Transmission repair and workshop manual for tech info.
Basically older transmission will begin to fail around 140k-200k if you do poor maintenance. Such as not changing the transmission fluid in time or using cheap transmission fluid or way past reg maintenance.

Every mechanic I spoke too mentioned I would need a rebuild transmission soon or a replacement transmission $3000 job for a $3000 Pathfinder. Not good investment or return. So I'm usually on top of my maintenance for all my cars and it didn't seem right for my pathfinder to start acting up. Regardless on how well you maintain your car, it's going to break down at some point.

I was told one option was to use seafoam in the transmission to free up varnish around the valves and clear up any build up of dirty transmission fluid from an aging transmission. This option is good if your transmission if it isn't wore out gears or bad clutch plates.
How to check for very worn clutch plates and chewed up gears by opening your transmission pan and check the magnet for metal filings. The Seafoam is good maintenance and keeping your transmission clean.
My transmission was clean no metal filings and just shifting issues and error P0744.
So the I checked all the solenoids on top and lower. The lower solenoid was not pulling the correct 10-20ohms.
You'll need a volt meter to check all the solenoids.
Line pressure solenoid needs to 2.5-5.0 ohms.
Shifting solenoids needs to 10-20ohms. These are found on top of the transmission plate. Which can be access once you pull all the bolts and drop the shifting plate.
This is very messy job so, lay down tons of cardboard and super wide pan to catch transmission fluid. It will leak another 3 quarts after you drain the pan.

I replaced the faulty solenoid and carb cleaners all the other solenoids on top for varnish and possible dirt.

[Pathfinder2002]

https://goo.gl/photos/AxnRfSC18B7CVfN67

https://goo.gl/photos/qdQEabZc9TC6fS3E9

[Pathfinder2002]

I"m sorry but I wanted to drop photo to this link and it seems it's very difficult.

After checking all the solenoids I replaced the rubber seals on all them. Since they are metric I found a rubber seal kit at harbor freights. These are the shifting solenoid seals and TCC Solenoids which help shift the car into drive in the morning.
This is the reason why the car fails to shift properly into D until it warms up. Once the oil heats up the rubber the seals fill gap better. Replacing will fix this problem.

Putting transmission back together is a little bit harder.
You'll have contend with 3 springs and shifter rod located in one openings that's cut out from the lower transmission unit.
You'll have to balance the lower transmission unit and keep it level to line up all the parts and push back into place.
What help me since I only had my two hands were a bungee cord and I found to point to attach each end.
Slide the lower transmission plate and keep all the springs line up for each section. Make sure to inline the gear shift rod.
Start to put back all the 35 blot which hold the lower transmission up.
I put back all the bolt in hand tight and went and slowly tighten up all bolt to spec.
Put back the clean transmission pan and 7 quarts of transmission oil.
The transmission shifted smoothly and in all gears. No more morning warm up to get into Drive.

[Pathfinder2002]

Also the error code went way since I had the battery disconnected for 4 days. Also I have ODBII reader and can clear error code that way too.
Clean solenoids and replacement the rubber seal can apply to really most transmission shifting issues.
The lesson learn for me was I didn't need a $3000 rebuild or replacement transmission.
I'm really disappointed that mechanics who I trust just wave a major expensive to resolve a simple problem.
Honestly, I'm sure this issue will come back at some point since the old solenoilds are still 14 year old but why replace them with new parts unless you have too. I would hate to go back into the transmission since it was messy job but I'm sure I replace those parts much faster since I know what's involved.
Also to help keep the 35 bolts in order I took a picture of the transmission and printed a color copy and taped to box.
Every bolt I took off fell on to color print out map.
So if you want to save some money, try seafoam and swap the transmission oil after 500 miles.
If that's doesn't help with shifting or cold morning shifts into Drive then replace rubber seals on all the solenoid that should help greatly.

[Pathfinder2002]

Pulling the transmission Filter and showing the TCC Solenoid bottom middle.

Note the transmission wires are held by plastic clips and retaining clips for electric male/female plugs to all solenoid and shifter solenoids. These clips and retaining clips all broke when taking them apart. Don't worry I thinks impossible not to break them.




The filter is removed and showing all the bolts that need to be removed to access the lower transmission.
Print this photo to create a bolt guide when removing and replacing back the bolts.



Once you pull the bolts and detach all the electric plugs you'll have access to lower transmission shifting plate.
Make note of the each spring location and the shifting solenoids are located to left.



Here are rubber replacement o-rings from harbor freights.




Here are the shifting solenoids for each gear. from 1st to 2nd gear and so on.
I tested each of these solenoid with a volt meter.
These were all good and if you look inside the wholes make they are clean free of debris. Also I used carb cleaner to free up any dirt and possible obstruction inside.
I took the replacement o-rings and change them out on all solenoids.
you can see the rubber o-rings on this photo too.


Here is the gear shifter make sure to replace back in the correct location when you put back the lower transmission.

[atraudes]

Wow, excellent writeup and followthrough! Sorry you didn't get any responses; I think most people here don't venture too far into the transmission. It's really cool to hear about folks dodging multi-thousand dollar bills with some good sense and elbow grease

I'm a little surprised Seafoam was recommended to you. I haven't heard that before. Transmission fluid is insanely good at cleaning things up and I've always heard that fresh fluid will clean up most problems.

I'd recommend you install a Magnefine filter if you haven't already. It's a great insurance policy, especially after investing in the transmission.

[Pathfinder2002]

Yeah I was told to used Seafoam trans tune.
Sea Foam Trans Tune
http://www.tooltopia.com/null-seatt16.a ... AsKh8P8HAQ

My buddy was having issues on his toyota pick up truck and wasn't shifting into overdrive and after a 16oz can in the transmission it began to free up. "Trans Tune® reduces rough or erratic shifting by dissolving varnish that contaminates transmission valve bodies, bands, governors, pumps and passages. Trans Tune® makes the perfect system flush for transmissions, power steering and hydraulic pumps, removing damaging moisture and deposits that impair system performance.".
Totally worked for him. Since he wasn't having any SES lights and had clean transmission fluid and still had bad shifts. This will not fix any broken solenoid of course so I needed to address that issue P0744 but the shifting issue would have been resolved. Since I pulled the lower transmission I performed the carb cleaner in the solenoid and changed the rubber seal that fixed the problem but at the cost of opening the transmission. Of course this is the correct way and Seafoam is temporary fix.

People who also are having 2001 shifting flare up this process will help them find the solenoids to replace.
P0740 issue can be address by finding the right solenoid in this write up too.
I hope this will help Patty owners with their next transmission problem.

[atraudes]

Oh nice, I didn't realize they had a separate transmission product. Good to know!

[Pathfinder2002]

Quick update after a couple weeks driving the Pathfinder, I've noticed the shifting is better because of the clean transmission oil and no more cold morning shifting issues. So replacing the bottom TCC solenoid fixed the P0744 problem and the new rubber o rings fixed the shifting issue.

[2001qx4guy]

Thanks for the excellent writeup. This is the most helpful information Ive found on this so far.
Im only planning on replacing the fluid, filter and TCC solenoid.
Im hoping you can tell me if the TCC solenoid can be replaced by removing only the filter or does the whole lower transmission need to be removed like you did?
Thank you.

[MisterH]

The write up with pix was very helpful! [FYI: what you're calling "the lower transmission" is the valve body assembly]

[attofarad]

Great write-up and photos. One concern I have is whether there might be a better material (such as ethyl-acrylate or maybe Viton?) for the replacement o-rings?

[604-Allstar]

Thanks for the excellent writeup. This is the most helpful information Ive found on this so far.
Im only planning on replacing the fluid, filter and TCC solenoid.
Im hoping you can tell me if the TCC solenoid can be replaced by removing only the filter or does the whole lower transmission need to be removed like you did?
Thank you.

Did you have to remove the whole "lower transmission"(valve body assembly) to get to the solinoids?