Towncivilian

There is only one on the front driveshaft for 4WD Pathfinders IIRC. A flexible hose will be helpful.

Actually 2001+ have a weaker rear LSD (significantly less breakaway torque), and 2003-2004 has an even weaker LSD than 2001-2002. If you get an open diff 96-2004 are all probably the same. 2001+ has a RE4R01A-HD (heavy duty) transmission which is beefier to back the VQ35DE. But other than that there are no differences between 96-00 more or less.

I suggest this ODB2 reader and Torque Pro ($5) if you have an Android smartphone.

You see that bracket next to the A/C low pressure line (with the green cap), with the gray plug attached to a bracket on the side of the engine? The gray plug is the original sensor's harness. Trace it back to find the sensor.

I don't know its exact location but it is on the passenger side. Removing the engine cover may help you find it. Its harness is connected to the passenger side too, there will be a red and a blue colored connector attached to a bracket if I recall correctly.

Get 12v microbulbs from Radio Shack, they are inexpensive and fit perfectly in hazard, defroster, A/C and recirculation buttons, and QX4 analog clocks.

That is the correct part. Did you use any discount codes?

See EL-87.

I don't believe the recall expires. If the rust is bad enough, it can condemn your vehicle which is why I suggested to have that inspected first before worrying about the oil pan, etc. Of course I don't wish anybody's vehicle to be bought back due to rust, but severe rust in the strut housing is very dangerous. Out of curiosity, is the transmission pan rusting as well?

Has your Pathfinder been inspected for the strut housing corrosion recall yet?

Worthless

I need the manufacturing date of your Pathfinder to determine which sensor is correct for your engine, which can be found on the driver door jamb sticker.

Yes. Mine is plumbed after the auxiliary cooler.

Magnefine is an inline transmission filter containing about 35 micron filtering media and a magnet similar to the one found in a transmission pan. All fluid is directed over the magnet so effectively all ferrous wear material is captured; this somewhat increases the overall efficiency of the filter. There is a bypass valve should the filtering media become clogged; even with the bypass in operation, all fluid is still directed over the magnet so some filtering is still being done. The filters cost around $20 shipped. You can find photos of its internals after 13k miles in use on my Pathfinder here.

OK, sounds good. Ideally after a trans failure the filter would be after all the coolers to catch any debris that may work itself out of the coolers, but that's in a worst case scenario if the trans grenaded and spewed junk throughout the lubrication circuit *and* the lazy salaried tech didn't flush the cooler(s) like he was supposed to. Your setup is fine, keep it as is. Your trans failure was not catastrophic so there shouldn't be a gigantic amount of debris in the aux cooler, especially because the filter probably caught it all already.

You can run the Magnefine for 10k miles I feel before replacement. Or if you're doing a full fluid exchange using the cooler lines, I would suggest to do that in 5k miles (most break in wear will have occurred by then) and replace the filter at the same time. Then do full fluid exchanges plus Magnefine replacement every 30k miles. Is the Magnefine plumbed after your aux cooler? What is the cooler rated for? If you don't know, provide its model number.

Bank 1 is the side with cylinder 1, in our case passenger side. Sensor 1 is the upstream sensor. If you can wait until morning I'll provide a link to the direct-fit Bosch O2 sensor (Bosch is the original equipment manufacturer) from AAP along with a discount code, and which size O2 sensor socket you'll need. It should be very easy to replace an upstream sensor, there's much less wire to snake around.

Change the fluid (drain & fill) in 1k miles and then in 3k miles and install a Magnefine. There will be new break in wear and crap from the rebuild process (the shop is not a clean room) you'll want to get out of there ASAP.

You used carb cleaner on the MAF? Or is that the "TB & Carburetor Cleaner" can? Either way, MAF sensor cleaner spray or isopropyl alcohol (preferably 91%) only!

Wouldn't a 96-97 D21 trans swap in without a problem too, and have the correct filler location? What about D22 (Frontier) transmissions? Many options here. Is any specific year 'beefier' than the other?

Did WD21 cloth seats have heated seats as an option? Do WD21 seats fit in an R50?

Yes, a transmission cooler is highly recommended even if you don't tow. That Hayden one is rated for 30k GVW, highest I've seen at a reasonable price. I have a B&M 70268 and it's 19k GVW; a B&M 70264 is thicker but otherwise has the same dimensions and is rated for 24k GVW. I'll probably upgrade to that Hayden unit eventually just for the hell of it, haha.

Good choices! √ I don't think your VG33E will receive any benefit from anything higher than 89 octane though. It specifies 87; it's reasonable that 89 might be beneficial if the engine can advance timing far enough, but 91/93 would be a stretch. I would also tend to run a fuel system cleaner in the tank immediately prior to changing the oil because some of the cleaner can get into the oil through fuel dilution. An admittedly very small amount, yes, but it can be prevented. I doubt it will cause any issues either way otherwise it'd be stated on the bottle's instructions, but I like to err on the side of caution. You know for next time.

Wow, big difference. Looks great. Nice work! I wonder how that rust got there, has your Pathfinder been in FL its whole life?

Wiper cowl?