Hi Everyone,

I have a 1999 Pathfinder that I'm having some trouble with. Two days ago the transmission stopped shifting up into overdrive on the highway. All other gears shift smoothly and at the proper rpm. The engine also runs smooth without any obvious issues.

Here is what I've done so far:

Road tested and verified that pressing the o/d button on the shifter didn't change gears or rpm.
Turned the key to "on" to see if the o/d light flashed, it did not.
Checked the AT fluid level and condition and all appears good.
There is a check engine light on but that is for a knock sensor I believe. I just had that checked recently and I don't think that is related to this problem.

I'm going to try disconnecting the battery for a while tonight to see if it will reset and work properly, but I'm wondering if you all have any suggestions. Has anyone out there encountered this issue or something similar?

I did a little internet research and I'm not finding much info. I found where someone suggested that the automatic transmission temperature sensor could be bad, but I'm having trouble finding information on the location. It could be inside the tranny, but it could also be a connector issue somewhere in there. Anyway, any and all help would be greatly appreciated.

I was having that problem on my 2001 (3.5 engine), and replacing the camshaft position sensor fixed it.

Thanks attofarad. Did you have other problems as well, or was it just that the vehicle wouldn't go into overdrive at the proper rpm on the highway?

I'm wondering why that would fix it .. CPS ??? The trans temp gauge has been known to do it

I had a similar issue once a few months ago. Although I did notice a slight drivability difference on mine, 2000 pathfinder LE. My Overdrive was not engaging and OD light would not turn on, on dash. I had a check engine light but I don't remember now what the code was, something like p07--. I checked the alignment of my neutral safety switch on the side of my auto trans and found that is was out of alignment. After I aligned the switch properly and erased the check engine light fault, the problem remained and the check engine light came back on. I then replaced the neutral safety switch with a brand new one, erased the fault and finally fixed the problem. My Overdrive worked normally and has since then. No more check engine light either.

I'm pretty sure that Mredggy had the same problem as me. After a while it showed the neutral safety switch code P0705. I'm working on replacing the switch right now. It's a pain because you have to drop the pan to release the switch. There is a small pin in there that you have to pull out so that you can slide the shift linkage out enough to remove the neutral safety switch. However, that pin does not want to budge. I've got a big pair of pliers on it and I'm giving all I've got and it will not move. I'll update if I ever get it off of there and test the new switch.

Ok, so I got the pesky pin out. It was really just a leverage issue. I ended up lifting the vehicle up higher (safely with jack stands of course) so that I could get more umph on it and I got it on the first pull with a larger pair of pliers. The good news is that my problem was resolved after replacing the neutral safety switch. The vehicle now shifts properly in all gears. The error code was P0705.

The job was rather difficult and part of it was my fault. You have to drain the transmission and pull the pan to get to that pin I was talking about. Once the pin is removed, you can gently pry the shift linkage away from the transmission enough to release the neutral safety switch and remove it. You just need enough space to disengage the pin from the shifter that changes the gears on the transmission from the little slot on the neutral safety switch. Its connected right there and you can remove the neutral safety switch once you disconnect the linkage. Of course, you also need to remove the 3 8mm bolts holding the neutral safety switch onto the transmission.

I spent too much time farting around with that pin instead of using common sense. Then I spent a good chunk of time trying to connect the two connectors from the neutral safety switch into the wrong plugs. I thought they needed to go up in the back of the engine bay on the passenger side and I messed with it for awhile and did a bunch of unnecessary research. I watched a YouTube video that showed the connectors connecting in the back of the engine bay on the passenger side and the FSM showed that there were AT connectors there. It didn't make much sense for them to connect there because the cable seemed too long for that and one of the plugs wouldn't fit. Anyway, I dug deeper into the FSM and found that there is a listing for neutral safety switch on the harness diagram. The correct section of the FSM is EL-325 and the plugs are B65 GY8 and B66 GY2. The B## is just the location on the diagram and the GY8 means the connector is grey and has 8 cables coming into it. Thus GY2 would be grey with two cables going into it. The cables actually connect under the rear passenger side of the vehicle above the exhaust. There is a little panel you can remove to get to the connectors up in there. Thanks so much for the FSM Nico Club, it was super helpful!

One more helpful tip on the install. The neutral safety switch is adjustable and if you don't adjust it right you might have trouble with it shifting properly. There is a hole in the lever on the neutral safety switch that lines up with a hole on the metal housing of the neutral safety switch. Mine had two holes in the lever, one at the top and one toward the middle of the lever. I used a 3mm allen wrench to hold the lever in place so that when I installed it, it lined up properly. First get the pin from the shifter engaged with the lever of the neutral safety switch. Then install at least two of the three bolts into the transmission housing, but don't tighten it to much so that you can move the neutral safety switch around a little bit. Adjust it until you can put the short end of the allen wrench through the hole on the neutral safety switch lever through to the alignment hole behind it on the body of the neutral safety switch. If you use the short end it kinda sticks in there and doesn't get in the way. Once you have it there, tighten at least two of the three bolts that hold it to the transmission body tightly. Then tighten the third and remove the allen wrench.

You might ask why I didn't trace the old cable in the first place. Well, it was really hard to tell where it went up in there. It's all greasy and dirty and hard to see and follow. I actually ended up just cutting the cable off of the old neutral safety switch to remove it. I didn't plan on that, but it was damn near impossible to remove the old cable and not worth the effort. I just left the old cable up in there when I replaced it.

I didn't have to remove the cat or any exhaust parts to get to it. I ended up using an impact wrench to remove the plug in the pan. I know you aren't supposed to do that, but the plug is really flat and it's hard to find purchase with a typical socket or wrench. It was on there super tight and I was going to round it off with the ratchet. Plus, I didn't want to drain it by dropping the pan. It would have been a huge mess.

It ended up taking 6 quarts of ATF to refill afterward. I wasn't expecting it to take that much as it didn't seem like that much came out, but I guess it did.

This post isn't meant to be a how to, but I hope some of the info is helpful to someone down the line. Here is a link to the YouTube video that I watched. It isn't great because it doesn't show the full removal and replacement, but I thought it was helpful. Just be certain to check where the cables from the neutral safety switch connect to your specific model.

https://www.youtube.com/watch?v=OQ4u6AAt1As

Thanks to everyone who commented on this thread! I appreciated the help.

So, I have a question. I just picked up a 2001.5 Pathfinder and pressing the OD button doesn't change anything either. Does that mean my OD is NOT working? When I cruise on the freeway the RPMs are around 2000 (if I can remember, didn't seem that strained or loud). When pressing the OD button, it usually locks out 4th gear, correct? So I'm confused: Is my fourth gear (OD) engaging or not?

It is engaging. If the light is not coming on, you don't have the ability to turn overdrive off. You may want to disengage it if you are climbing or descending hills, or pulling a trailer.

rgk wrote: ↑

Mon Sep 16, 2019 5:27 pm

It is engaging. If the light is not coming on, you don't have the ability to turn overdrive off. You may want to disengage it if you are climbing or descending hills, or pulling a trailer.

Right, that's what I thought. The original posting made it sound like OD was not engaging. Thanks for the clarification

Your '99 Pathfinder and my '02 (and I think all '96 - '04) with automatic transmissions have 4 gears only. "Overdrive" can mean very different things (different functions) depending on the type of vehicle so it can be confusing when one good explanation of what "overdrive" means is actually not applicable to our Pathfinders. For our Pathfinders ('96-'04), saying that it doesn't shift up into overdrive while driving on the highway is not accurate if you were already going at least 40 MPH. Our OD OFF light on the dashboard indicates how our transmission will behave differently when it shifts gears not if it will shift into 4th gear. If you are driving with the OD OFF light off, then you are already in "overdrive" and have been throughout every gear shift. The difference is that with OD OFF engaged (dashboard light is on) our transmission shifts at a higher RPM than when we are driving in overdrive (dashboard light is off) By the time you got on the highway you were likely already in 4th gear so there was no shifting up that was going to happen. OD OFF should only be engaged on steep hills or towing a trailer and possibly even stop-n-go traffic or around the neighborhood where you won't be going over 35 MPH. Even then, cruising at 35 MPH, your transmission will shift into 4th gear with overdrive off. The torque converter will "decide" when to shift depending on what mode you select. Having said all that just for Pathfinder edification, it sounds like you have something going on that's not quite right but I'm not sure what might be going on. There are specific diagnostic trouble codes for V6 models that could be stored and obtained using the OD OFF light on your dashboard. The Haynes Repair Manual, Chapter 7 Part B has a great process explanation for this but first your OD OFF light needs to be working. If you can turn the light on then this manual might help a great deal. If you had a knock sensor trouble code when your check engine light was on, that might just be a symptom caused by some other issue with the powertrain related to your transmission.
At least I hope so because Nissan buried our knock sensors underneath the intake manifold along with the PCV valve making a simple maintenance thing into a top end engine tear down, but I digress. I hope some of this was helpful.

I have recently replaced the neutral safety switch on our '98 Pathfinder so I thought I would do a follow up on Meter6's post. I had also lost overdrive and the scan code said neutral safety switch.
The entire neutral safety switch setup is one of the worst engineered things I have ever seen. Surely the pin in the shift arm lever could have been made removable. I looked for a way to remove the old switch without having to pull the pan but failed to find one. To my pleasant surprise the pan gasket stayed on the pan and was in perfect condition.
The pin. It is actually a long roll pin. I completely screwed up it's removal by doing it the difficult way. After I got it out I realized all I had to do was grasp it in a vice grip, then use a bar or whatever would fit to put downward leverage on the vice grip, and pull it out.
On mine, to get the shift shaft far enough over to remove/replace the switch I had to slide the shifter detent plate on the shift shaft clear off the spring loaded detent roller. When I did that, this sliding rod that sits in a channel facing toward the transmission rear disengaged. It can slide rearward and completely disappear in it's channel. Ask me how I know. Fortunately that channel is open at the rear. I ran a wire in through the rear and pushed that rod forward again. After installing the new switch arm over the shift rod pin you have to do all these things at the same time: Push the shift shaft toward the inside, and lift the spring detent roller up with a long screwdriver so the detent plate can slide under it while at the same time making sure that pesky channel rod engages it's engagement pin.
Now, that pin. The purpose of that pin is to limit the left/right movement of the shift shaft. Really Nissan? A 1 1/2" roll pin that is fragile and could easily be broken off? I didn't have a new roll pin that size and I sure didn't trust the old one. I had some pieces if spring steel wire. I bent one into the appropriate shape, slid it int to hole and thus engaged with the groove in the shaft, and pinned it under the closest valve body bolt. Given the only purpose of that pin is to limit left/right shaft movement, there really isn't any pressure on that pin, and given the material I used is spring steel, and I bent it so there is a slight upward bias, I'm pretty sure that removable pin will work just fine.
A test drive revealed everything works and overdrive engages again. I installed Dexron VI synthetic fluid and I'm hoping going with synthetic turns out to be a good decision.
Looking back I am wondering if I missed something. Would it be possible to remove/replace that switch by doing this: Remove the three hold down screws, swivel the switch roughly 180 degrees upward, and roll the switch arm off that pin, start the new switch upside down and somewhat inside out, roll the new arm onto the pin and then swivel the switch back 180 degrees into it's normal position? I think if one had their Pathfinder up on a lift that might be possible.