bmitchell Posted March 18, 2011 Share Posted March 18, 2011 (edited) I know it's been a while since I posted but I've been super busy with all sorts of craziness. Anyway, here's what's up. 94 Pathy SE, auto trans. I've had this thing for about six months and I love it. It ran great until the past month and still runs fine in certain modes. When I've got my selector in D, everything is fine for 1 and 2. When it should be shifting to 3 (around 35-40MPH from the shift schedule chart I have) it instead seems to be shifting to 4th or possibly 4+lockup (5?). RPMs shoot up over 3-4k and speed drops off. It still pulls if I rev it higher but it doesn't feel like 3rd - have to get it up over 4k to feel it pull, which is gradual, not like a downshift - just very low torque. Reverse, neutral, 1 and 2 work great. Park is fine too. 4/4lockup seems normal but hard do say without redlining it in 2 to get up to speed. It feels like it is just skipping over 3rd. The first time it did this I was in a bad mood and wasn't paying much attention; the AT got pretty hot. I live on a mountain and it was fine the first time I drove down and back up, then I went down to get something else and on the way back up (about a mile from home) it started doing this. For a little while, if I gave it enough throttle it would downshift back to 2, but it is picky about doing that now. No error codes from the ECU if I am reading it correctly. No Check Engine indicator. I've been through old slip threads and all sorts of google pages, not to mention the FSM, but nobody seems to have this exact problem and the FSM says narrows it down to the accumulators, which it doesn't say what to check for. I don't think the TC could be a problem or it'd be apparent in the other gears. My first check was the TPS but it checks out fine. My second would be VSS but if I understand the year/model correctly it would show oddities in the speedometer if it were faulty, which it doesn't. I have twice drained the ATF and refilled as indicated but each time I only get about 4QT out of the 9QT total. I haven't done a complete flush from the lines and internal pump yet, just from the AT pan hole. I have a new gasket and filter for the AT pan but I thought I'd ask before I got under there what I might look for. If I read the service manual correctly the AT has its own self-test, which I have not performed yet since I didn't know the procedure. This is top of my to-do list tonight. EDIT: Self-test shows 10th judgment flicker, indicating a problem with the Line Pressure Solenoid Circuit. Will continue diagnosis. Any suggestions? Vacuum line? Solenoid? Accumulator? Valve? Controller? I'm pretty much a noob when it comes to ATs- are the accumulators the same as the valves? Is this considered slipping or flaring? Also, I think there's something wrong with the 'other' VSS - ABS and brake indicators come on but the fluid level is good and the ABS seems to be working. Indicators go off if I turn hard left so I could have a shorting wire or something. Ben Edited March 18, 2011 by bmitchell Link to comment Share on other sites More sharing options...
bmitchell Posted March 18, 2011 Author Share Posted March 18, 2011 Ok - so now I'm failing on step B (subharness to connector 33) of the line pressure valve solenoid circuit check. Had to take off several interior panels to get to one little unit - why would they not put in an access panel...I don't get it. So - dropping resistor for the circuit is possible - may need to be rewired since step C (subharness to connector 34) is also NG. Much farther in one day than I've been all week. Will report back later. Ben Link to comment Share on other sites More sharing options...
bmitchell Posted March 18, 2011 Author Share Posted March 18, 2011 I know this might be a dumb question -- especially since I am staring at the wiring diagram... To what should the dropping resistor be connected? Since I started I did not disconnect it but it is plugged in to nothing and there doesn't seem to be any connector of a similar shape anywhere. Also -- I know nobody touched it between normal operation and problem operation. I would take a photo but nothing is plugged in to it. I'm sure one can imagine a non-connected dropping resistor. Ben Link to comment Share on other sites More sharing options...
bmitchell Posted March 22, 2011 Author Share Posted March 22, 2011 (edited) Ok - so what I am looking at now is this. The brown/yellow cable into the AT control unit is supposed to be connected to the dropping resistor, which is supposed to be a second link off of the green/yellow that is checking out currently (where I posted step C failed I was wrong; the FSM calls two different things "port 34" (three actually)). So why don't I have a green/yellow and brown/yellow plug to connect to the dropping resistor, and since I don't have one, where does the brown/yellow come in to the engine compartment, and if it was just disconnected at some point, shouldn't it be spliced into the green/yellow cable? Here we see, arrowed in green, the dropping resistor and its unplugged connector, circled in green. What to plug in to this is my conundrum. The mauve arrow points to some jumpered connection that seems a likely candidate for being the bypass. Does anyone know what this is? At this point I am skeptical that this has anything to do with my problem since it obviously isn't wired correctly and hasn't been since I bought it, though it worked normally for months before the problem condition. Ben Edited March 22, 2011 by bmitchell Link to comment Share on other sites More sharing options...
Finder98 Posted March 22, 2011 Share Posted March 22, 2011 I had a similar problem with my 88 when i owned it. Its not the same thing that you are describing though. When the pathfinder reached 45 to 55 mph it use to stay at that speed and rev to about 4000 4500 rpm. My first thought was the transmission was toast and the clutchs were slipping. So i brought it to a trans shop and got them to look at it and it turned out to be a line air locked. Only cost me 50 bucks to get it fixed. Better than having a trans rebuilt. Dont know if this helps any with your problem. Post when you find out the problem and good luck. Link to comment Share on other sites More sharing options...
bmitchell Posted March 23, 2011 Author Share Posted March 23, 2011 I had a similar problem with my 88 when i owned it. Its not the same thing that you are describing though. When the pathfinder reached 45 to 55 mph it use to stay at that speed and rev to about 4000 4500 rpm. My first thought was the transmission was toast and the clutchs were slipping. So i brought it to a trans shop and got them to look at it and it turned out to be a line air locked. Only cost me 50 bucks to get it fixed. Better than having a trans rebuilt. Dont know if this helps any with your problem. Post when you find out the problem and good luck. That actually sounds a lot like what mine is doing - the actual MPH of the flare would differ based on other factors I'd guess. Was it a fluid line or something else? Ben Link to comment Share on other sites More sharing options...
Finder98 Posted March 23, 2011 Share Posted March 23, 2011 It was a fluid line not sure of the exact line though. They said that there was a air pocket traped in the line. I have no idea how it got there eather because I had the truck for 2 years befor it happend and I changed the fluid when I first bought it. I had the trouble when I was going down a hill doing about 50 55 mph and turned the over drive button off. Rpm's shot up to 4500 and stayed like it. Link to comment Share on other sites More sharing options...
bmitchell Posted March 24, 2011 Author Share Posted March 24, 2011 Gotcha. I'll check that when I do a flush. Link to comment Share on other sites More sharing options...
bmitchell Posted June 26, 2011 Author Share Posted June 26, 2011 Well, two flushes, several attempts at other diagnoses, a dismissal of the dropping resistor circuit as anything related, and one small fire later and it is being rebuilt. Long story but it definitely burnt up on the road about a week ago. Looks like a hose came loose on the road and splashed hot ATF all over the exhaust which flared it up. Towed to the shop, one rebuild in progress. All sorts of things wrong with it. The shop had almost everything done then they called me and said that somehow now my rotation sensor is cracked but they aren't charging for its replacement. Very odd. Also now I own a fire extinguisher. Why couldn't I have learned from all the people who said to get one? Had a wedding to be at this weekend so no work on the pickup (though it is now in reassembly phase). Ben Link to comment Share on other sites More sharing options...
DOA Posted June 29, 2011 Share Posted June 29, 2011 Holy crap an air pocket!!!!! I had this same problem and I swapped my whole tranny out for a manual one. Oh well. Link to comment Share on other sites More sharing options...
silverton Posted June 29, 2011 Share Posted June 29, 2011 Since you're getting it rebuilt (most people on this board will tell you that a stock wd21 automagic is not worth rebuilding, me included) buy an aftermarket transmission cooler and just forget the one in the radiator! I suggest a flexalite transcool 4116. the 16,000 pound cooler. It will help with the longevity of your freshly rebuilt transmission. Link to comment Share on other sites More sharing options...
bmitchell Posted June 30, 2011 Author Share Posted June 30, 2011 (edited) Didn't have the luxury of waiting for them to do anything extra - I will be adding an aftermarket trans cooler as soon as it is feasible. I have it back now - shifts like a charm (as I'd expect from a rebuild). They mentioned the option of an upgraded valve body - not sure what this meant and they didn't go into detail. We shall see. Now my oil light is acting up. The light is bright when idle but dims when I rev it. The oil pressure switch is missing the harness for the wire but it appears to possibly not matter...kind of low on info about it since the FSM only mentions to remove it to check oil pressure and how to test the voltage. I also noticed my CV boots are ripped a little on the front - then I noticed a note from the trans shop saying the same (they also mentioned the oil sensor but said it had a leak which I don't see). Edited June 30, 2011 by bmitchell Link to comment Share on other sites More sharing options...
silverton Posted June 30, 2011 Share Posted June 30, 2011 Upgraded valve body would have made it shift firmer and prolonged the life. the light shouldn't be on ever, unless it's not plugged in, sounds like it's grounding out somewhere from not being plugged in, not sure what you mean by harness is missing... Link to comment Share on other sites More sharing options...
bmitchell Posted July 1, 2011 Author Share Posted July 1, 2011 (edited) Upgraded valve body would have made it shift firmer and prolonged the life. the light shouldn't be on ever, unless it's not plugged in, sounds like it's grounding out somewhere from not being plugged in, not sure what you mean by harness is missing... Unless I am looking at the wrong thing, it is not plugged in to anything and it looks like the wire just ends. Posssibly it was damaged when the ATF flared up but nothing else down there seems to have been affected. I know the light wasn't on before the trans problem. I can't seem to find it in the EL section of the FSM except for the section on checking its voltages which does not tell me where it should be plugged in. However...what is really odd is that the light will flutter and go off if I am around 3k RPMs, so I don't know how that is possible without it being connected. I'm going to pick up a new pigtail connector for it and see. Ben Edited July 1, 2011 by bmitchell Link to comment Share on other sites More sharing options...
sewebster Posted July 1, 2011 Share Posted July 1, 2011 (edited) Unless I am looking at the wrong thing, it is not plugged in to anything and it looks like the wire just ends. Posssibly it was damaged when the ATF flared up but nothing else down there seems to have been affected. I know the light wasn't on before the trans problem. I can't seem to find it in the EL section of the FSM except for the section on checking its voltages which does not tell me where it should be plugged in. However...what is really odd is that the light will flutter and go off if I am around 3k RPMs, so I don't know how that is possible without it being connected. I'm going to pick up a new pigtail connector for it and see. Ben It's coming on and off because the wire is loose down there somewhere and it touching ground (light goes on) and then coming off again (light goes off). Or at least that is the most likely reason. If you are saying the the oil pressure wire "just ends" then yes, put a new connector on it and plug it back in... Edited July 1, 2011 by sewebster Link to comment Share on other sites More sharing options...
bmitchell Posted July 3, 2011 Author Share Posted July 3, 2011 (edited) That is what is going on - it looked odd because I wasn't sure I was looking at the right thing at first - it is definitely shorting against the side of the engine. Looks like the wire melted in the middle - probably from the fire I guess? Oh well - as soon as the exhaust shield cools down some I'll splice them back together. Edit: Done. All is good. Thanks for the help! Edited July 4, 2011 by bmitchell Link to comment Share on other sites More sharing options...
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