Falling out of 4th Gear

[Guest gonefishin]

1996 Nissan Pathfinder LE,3.3L, 4Spd 4WD AT, 100k miles

 

Hello, looking for some help/advice--hoping someone has encountered this phenomenon and/or can list some potential root causes.

 

Symptoms:

At fwy speeds the O/D kicks off intermittently. The "O/D Off" never

illuminates on the dash but the RPM's jump up around 1300 RPM's (from about 2700 to 4000) at 70mph as if the overdrive went off or the transmission downshifted. This phenomenon is evident on perfectly level ground (no hills) where the throttle position is not varied and it even happens when in cruise control. After several seconds (roughly 10-30 sec.) of kicking out of O/D, the O/D will reengage automatically without any change to the driving conditions. All

other gears prior to overdrive do not exhibit any problems. Even O/D works well when it's not falling out of gear. Another note (that I am not 100% certain about): This phenomena appears to happen more frequently when the engine is colder (i.e. during the 30min. of travel) and then the problem appears to go away. Are there any solenoids/sensors in the valve body and/or transmission that would be thermally sensitive which would cause the problem that I am encountering?

 

More info:

I've had two mechanics hook up a scanner and there are no faults whatsoever. In addition, the check engine light is not on and has never come on. I've also had the tranny fluid drained along with installing a new gasket/filter kit. The problem has been evident before and after the flush. The old tranny fluid was very clean/clear red in color with no dicernable residue.

 

Another observation (may or may not be related):

According to owner's manual, the "O/D Off" light on the dash is one of the lights that should go off after a few seconds after turning the key to the "ACC" position. However, with the O/D button physically disengaged (out position), the "O/D Off" light on the dash never goes out. Is the computer seeing a problem or was this a misprint in the manual and in fact that light on the dash should be in the category of lights that should remain on?

 

Where do I go from here? What should I check?

 

Thanks in advance for the help.

[Nick]

You get 70mph at 2700 RPM? i wonder if thats something with the autos, my manual i get 70MPH at 4000 RPM, but then again maybe my speedo is off cuz at 70 im passing people like crazy.

[Nick]

But to answer your question it just sounds like its downshifting, because you say that the OD OFF light never comes on. And if im correct i think on the pathy you have to push the OD button to turn in on and off. I mean it is possible that it could be popping out of overdrive and it wouldnt say that its off because the button you push actuates the dash on the light. I know i didn't help but im just giving ya my 2 cents.

[sw]

i think i mentioned it before, but it sound like either one of the bands has shifted - heard of it happening before (i think it was angel that had this problem???) or one of the solenoids is in the process of spitting it.

what i would do is take it to a TRUSTED auto tranny shop, explain whats goin on and they should be able to help. it might be expensive but auto tranys are a science to themselves. i would check it out before to long other more damage might be done. hope this helps

[Blizzardking]

You get 70mph at 2700 RPM? i wonder if thats something with the autos, my manual i get 70MPH at 4000 RPM, but then again maybe my speedo is off cuz at 70 im passing people like crazy.

Nick, I definetly think your speedo is off Dont take this the wrong way, I am not laughing at your situation. It's just that I can picture you passing all these people doing 90, thinking your doing 70, thats all At 65-70 on my manny i'm at between 2700-3000 rpm's. So what he says sounds about right, even though it's an Auto. Take care...........

[Nick]

Haha ok, maybe i should slow down then I thought it was a little odd that i was hitting 4000 RPM on the freeway. O well thanx for the info

[Mookie]

These auto/overdrive Nissan Trannys aren't the best at overdrive I've noticed. When I was in stock form, I would get constant shifting in and out of overdrive on the highway on level ground with no headwinds. I could rarely use it.

 

I've read that a few people experience that the Frontiers/Xterras overdrive won't work well until they are warmed up. Maybe the newer Pathys are the same? Jim has newer Pathy too, maybe he's noticed something.

[sw]

Jims is many...

[MrJim]

I wondered if you were on hills. Anyway, my 96 shifts fine. If you were not on any hills then I don't know. It might be time to talk to a transmission shop.

[IndianRider]

mine was doing that on level ground too at around 100K miles .. so i changed the tranny oil and filter and made sure that the tranny oil level was up to the mark and its running great now ..

 

make sure u check the tranny oil level after properly warming up the engine/tranny and check it while the engine is running .. it took me 3 or 4 days of driving and repeated checking to get the tranny oil up to the mark ..

[vengeful]

Also, if you're driving into a strong headwind, or at a higher altitude than normal, the engine will have to work harder to maintain speed.

 

*Holy old post batman!!*

[Guest 97FINDERSCV]

Im having the same problem i dont know what to do im going crazy time to sell the beast!!!!! Sorry to say i knew i should have got a manuel trans. damn.