Hi Pathy friends,

I'm shopping for a Pathfinder for my nephew, he doesn't have a lot of money, is 20 years old and doesn't know yet how to drive a manual transmission. I'm shopping the R50 (96-2004) Pathfinders for him, looking for something reliable.
Mostly what I see under 2k usually has serious body damage or engine issues. But I'd say, overall, the most common issue I see listed is that the reverse isn't working in the transmission. So, what's the story here? Are all these Pathfinders doomed to either the scrap heap or thousands of dollars for a new transmission? Or is there a common fail point that is fairly inexpensive to fix? I keep hearing about some sort of solenoid in the transmission for reverse that goes out, but I'm not finding out if this is the fix 99% of the time, or what? If you've had issues with your reverse gear going out I'd love to hear your story.

- Dave

That is a common symptom/failure for the transmission. The short of it is: No, it's not an easy/inexpensive fix, hence the reason you can find them for sale with this condition. The age of the vehicles plays into this also. You can take to a tranny shop for a rebuild, replace it altogether (tranny) or sell it (vehicle).
I received a free pathy from my uncle (for my son) that had a crappy body with an excellent drivetrain. I found one with an excellent body, higher miles, and a tranny that wouldn't go in reverse. I swapped the engine and tranny into the better body unit. Replacing just the transmission is merely a P.I.A. Replacing the engine and tranny is enough to make you call the junkyard for a pickup

One reason for failure is the cooler portion of the tranny (the bottom part of the radiator) can crack where the tranny fluid is separated from the anti-freeze. Outwardly you can't see any issues since the crack is still inside the radiator. The antifreeze contaminates the tranny fluid and flows into the transmission...causing a failure. The prevention for this is to add an auxiliary external tranny cooler and bypass the radiator altogether.

moymurfs comments sound more like he is talking about the 05-10 R51 Pathfinder rather than the R50 Pathy. The radiator cooler issue is common on the R51, not the R50. I've never heard of or seen any cooler failures on R50's to date. That doesn't mean they can't or never happen, but keep in mind I worked from 1985-2003 in NJ and never saw or heard of a radiator cooler failure occur in a Nissan radiator until the problems occurred later on the 05-10 Pathys/Xterras/Frontiers. That would incline me to think that the occurrence on other year/model Nissans is pretty rare.
Also, solenoid issues are a problem with the R51 in that when they fail, it is very hard to find just the solenoid; you usually have to buy the very expensive, transmission valve body assembly, which comes with all of the solenoids and the TCM.
Solenoids shouldn't be an issue with the R50; the come as a solenoid pack assembly and aren't too bad to replace. You have to remove the pan and loosen the attaching bolts of the valve body to lower it (use a service manual schematic; you do not need, nor want to, remove all of the bolts in the valve body). You'll have to unplug the terminal cord and remove the clip at the case and route the terminal cord through the hole in the case. Once the solenoid pack attaching bolts are removed, carefully use a flat blade screwdriver or similar tool to pull the solenoids out of the valve body. Install fresh ATF on the solenoid seals and reverse procedure to install, making sure you use a torque wrench on the valve body attaching screws. I believe it's 72-inch/pounds. Over-tightening can warp the valve body. Nissan recommends replacing all 21 trans pan bolts with new Nissan bolts, as they come equipped with sealant on the threads. If you don't want to replace the bolts, at least clean the bolts with break cleaner and smear a little RTV silicone sealant on the bolt threads. I prefer the genuine Nissan pan gasket. Do not use Dexron III/Mercon! Use Nissanmatic Type "D" ATF or an aftermarket ATF that is recommended for use in Dexron/Dexron II applications (typically these are synthetics, like Castrol Transmax J Multi-import ATF or Valvoline Maxlife ATF).
THAT SAID: you may or may not have a solenoid issue and you need to do some diagnostics to be sure. Another possibility, which occurs on a number of automatic transmissions and not just Nissans, is the reverse drum snap ring may have popped out of it's groove on the drum, which prevents the clutch frictions and steel plates from compressing together when the drum piston applies pressure to them. The fix for this is expensive, as you will have to remove and teardown the transmission, replacing the reverse clutch drum assembly, or at least the drum and snap ring. Common sense would dictate an overhaul of the entire transmission due to the age and probably high mileage, at this point, or a replacement transmission.
A resistance check of the solenoids and a stall speed/line pressure test of the transmission would help diagnose the problem, the later requiring a set of transmission oil pressure gauges and a service manual or similar transcript of the test procedures and specifications.