95shakinPF Posted February 22, 2009 Share Posted February 22, 2009 (edited) Hey Guyz n Gals, its been a while since I've posted(got a new to us house and been remoldeling). Yesterday morning about 8am I tried to crank my truck(95 2wd A/T) to find the door wasnt closed completely so the dome light stayed on all night and drained the battery. I pulled our ford ranger over to it and jumped it off and she fired right up. I left it running approximately 30 mins to let the battery recharge and then turned it off. I tried cranking it again to see if the battery had in fact charged up and it fired off...problem solved I think. Later that day at 4pm I get in and try to start it and its dead again. Again I jump it off and it fires right up. This time I drive to town and back to get the rpm's up high enough to charge the battery fully. While I'm driving I notice the pathfinder hasnt near the power as usual. I turn down the music and start listening and trying to figure out whats going on. I find that its shifting strangely. It wont down shift when you "get on it" It seems to shift through all gears just fine when taking off from a stop, but once in overdrive it wont downshift into"passing gear". I did notice also that the button on the dash for A/T Power/Economy doesent light up when you stomp it like it used to. I did switch it to power and it does the same thing...no downshift. If you stop at a stop sign or traffic light it does take off from 1st gear again. It just wont downshift while driving. Has anyone experienced something like this before? What should I check? I already checked the A/T fluid and it is full. What could a dead battery do to affect the transmission from shifting correctly?...Im confused! Please help with some ideas. Thanks Edited February 22, 2009 by 95shakinPF Link to comment Share on other sites More sharing options...
Precise1 Posted February 22, 2009 Share Posted February 22, 2009 As for the battery, it either won't hold a charge or you have developed a drain. Do you have a voltage gage? If not, use a volt meter at the battery to see what the voltage is before starting and while running. It could be that you don't have sufficient voltage with the motor running. If this would affect the A/T, I don't know. I'm new to them... B Link to comment Share on other sites More sharing options...
alexrex20 Posted February 23, 2009 Share Posted February 23, 2009 an alternator doesn't have the capacity to actually recharge a battery. all it can do is keep a battery from getting drained while the vehicle is running (by providing its own ~14 volts to power the vehicle). if you ever discharge a battery, use a proper battery charger, or take it to AutoZone/Wal-Mart or wherever you purchased the battery. they should recharge it for free. i'm not familiar with the WD21 pathfinders, but it sounds like you have a vacuum leak. older transmissions (pre-electronics) use vacuum to maintain/adjust line pressure, which is then used to decide when and how aggressively the transmission will shift. i'm not sure that your transmission operates in such a way though. it definitely makes sense, considering you also noticed a loss of power - which a vacuum leak would also cause. try and listen for a whooshing sound under the hood. also, you can back-trace all the vacuum lines going into your intake manifold/pipe/airbox. Link to comment Share on other sites More sharing options...
95shakinPF Posted February 23, 2009 Author Share Posted February 23, 2009 Thanks for the input guys I think the battery is ok now because I drove it about 60 miles last night and it has been cranking fine now. However I will go by one of the auto parts places to let them double check and see if it is holding at 14 or so volts. I had assumed since all was fine day before yesterday that the shifting problem was due to low voltage somehow. Good advice on the vacuum lines tho. I will be looking into that tomorrow, early. Are you guys familiar with the E-A/T switch that I refered to? What does this actually operate? I've got a suspicion that this is somehow related to my problem,but not sure what it is really for. Link to comment Share on other sites More sharing options...
alexrex20 Posted February 23, 2009 Share Posted February 23, 2009 Thanks for the input guys I think the battery is ok now because I drove it about 60 miles last night and it has been cranking fine now. However I will go by one of the auto parts places to let them double check and see if it is holding at 14 or so volts. I had assumed since all was fine day before yesterday that the shifting problem was due to low voltage somehow. Good advice on the vacuum lines tho. I will be looking into that tomorrow, early. Are you guys familiar with the E-A/T switch that I refered to? What does this actually operate? I've got a suspicion that this is somehow related to my problem,but not sure what it is really for. E-A/T is a tow mode which keeps the transmission from upshifting too soon/often. it keeps you in the powerband, and also helps prevent overheating due to frequent shifting. if your transmission has E-A/T, it is electronically controlled and thus probably does not use vacuum to regulate line pressure. in that case, try checking the fuse(s) and/or fusible links for the E-A/T. Link to comment Share on other sites More sharing options...
94extreme Posted February 23, 2009 Share Posted February 23, 2009 an alternator doesn't have the capacity to actually recharge a battery. huh? that's simply not true. the alt does charge the battery.. that's one of it's funtions. the e-at button does move the shift points down. it's not just for towing but anytime you need some extra power. works well on inclines etc.. is the CEL on 95shakin? Link to comment Share on other sites More sharing options...
alexrex20 Posted February 23, 2009 Share Posted February 23, 2009 huh? that's simply not true. the alt does charge the battery.. that's one of it's funtions. the e-at button does move the shift points down. it's not just for towing but anytime you need some extra power. works well on inclines etc.. is the CEL on 95shakin? perhaps i should've been more specific: an alternator can not recharge a dead battery. if the battery was completely discharged, the cells have probably been permanently damaged. regardless, an alternator has a built-in regulator which only allows it to charge up to ~14v. it does not have the amperage output at that little voltage to efficiently recharge a battery (say, one that's down to only about 11V). Link to comment Share on other sites More sharing options...
88pathoffroad Posted February 23, 2009 Share Posted February 23, 2009 The trans has no vacuum lines, and a dead/dying battery can cause shifting problems due to the trans not getting enough voltage. Get your charging system checked asap! Link to comment Share on other sites More sharing options...
Kingman Posted February 23, 2009 Share Posted February 23, 2009 (edited) There's no vacuum lines for the trans. Like 88 said, poor voltage will cause the transmission to behave strangely. Edited February 23, 2009 by kingman92010 Link to comment Share on other sites More sharing options...
Kingman Posted February 23, 2009 Share Posted February 23, 2009 And the transmissions in the WDs and the R50s are the same, except the 87 3-speed ones. Link to comment Share on other sites More sharing options...
alexrex20 Posted February 23, 2009 Share Posted February 23, 2009 And the transmissions in the WDs and the R50s are the same, except the 87 3-speed ones. among the years, there were 3 different transmissions available in the US. Link to comment Share on other sites More sharing options...
95shakinPF Posted February 23, 2009 Author Share Posted February 23, 2009 No MZ CEL is not on. Kinda wish it was...I'd have something to go with. Thanks 88, and kingman, I'm headed to get it checked right now. I'll report back. Link to comment Share on other sites More sharing options...
Kingman Posted February 23, 2009 Share Posted February 23, 2009 among the years, there were 3 different transmissions available in the US. I was referring to the 4 speed automatic. Link to comment Share on other sites More sharing options...
94extreme Posted February 23, 2009 Share Posted February 23, 2009 No MZ CEL is not on. Kinda wish it was...I'd have something to go with. Thanks 88, and kingman, I'm headed to get it checked right now. I'll report back. autozone will check it for free.. maybe others too. i can't remember if the ecu has a mode to check the charging circuits but the write up in the "how to's" will tell you for sure.. and you could check it yourself too but you'll need a volt meter to do that. Link to comment Share on other sites More sharing options...
95shakinPF Posted February 23, 2009 Author Share Posted February 23, 2009 (edited) Update: I've just returned from O'reileys auto parts. According to their machine, the battery is fully charged and sits at 14.4V. The alternator is charging at 14V also with a 48amp output while running. Although I think that is a little low the worker says it is normal and ok. He also checked the starter's draw on the system and said its fine also. I checked all fuses under hood and dash and all are good. I also inspected fuse links at positive battery terminal and all of those look fine. So I guess I can now rule out the battery and charging system affecting the tranny. Does the E-A/T switch on the dash control something internal in the tranny or is there a control box or the like externally? What tells the transmission to shift into "passing gear" when you floor it? As I said,it shifts from dead stop through all gears but once it is in O/D it will not downshift until you actually stop(or slow to a crawl). Do you guys think this is just a coicidence that this happened when my battery got drained and now my transmission is starting to fail? Again, thanks for all your input and suggestions. It is greatly appreciated. Edited February 23, 2009 by 95shakinPF Link to comment Share on other sites More sharing options...
Kittamaru Posted February 23, 2009 Share Posted February 23, 2009 Hm, that's strange sounding for sure - my truck did this for a few days just before I replaced my spark plugs (but they were fouled as hell) and wires... I think that was coincidence though, and since the new plugs have gone in she's been good cept for running a bit rich *shrugs* Link to comment Share on other sites More sharing options...
k9sar Posted February 23, 2009 Share Posted February 23, 2009 (edited) with the dead battery issue, I would have suspected that youhad bad cable to post connections. Not enough juice from battery to run or to be charged but when you jump, you connect to the cables, not the terminals. If you frucked with the battery cables in any way, either by testing them or hitting the cables one one of your jumps, you could have reestablished the conenction. I would pull the clamps, clean the posts and reseat them. That's step one. As for the shifting, the E/AT affects the tranny control module and the ECU. As posted earlier, it changes when the tranny is told to shift. You need to further characterize the shifting issue... does it shift from D4 to D2 if you stomp on the gas? What does it do when you turn off overdrive while it's in D4? (Downshift or not). Does it downshift from D4 or D3 if you move teh selector from D to 2? If you need, I can host an electronic version of the AT section of the FSM for a bit if yu want to download it. It contains diagnostic procedures etc. as well as good wiring diagrams and such. Edited February 23, 2009 by k9sar Link to comment Share on other sites More sharing options...
Kingman Posted February 23, 2009 Share Posted February 23, 2009 (edited) That really sounds like an electronic problem. If it's keeping the gear, that usually means there's sufficient fluid pressure to hold it. If there wasn't enough pressure, it would "fall" out of gear, or not shift into a higher gear at all. On mine when my stock tranny cooler plugged up(mechanical fluid pressure problem, not electronic), it would downshift at retarded times, sometimes dangerously raising the RPMs (downshifting from 3rd to 1st, totally forgetting there was even a 2nd gear in there). This is because the fluid pump works from the rotation of the rear wheels, slowing down the rear wheels would cause it to not keep up with the amount of pressure the tranny needed when the tranny cooler wasn't circulating it properly, in effect causing the gear clutches to disengage and fall out of gear. If it's downshifting properly while slowing down (I forgot what the points were) and upshifting normally (again) on acceleration until overdrive, it sounds like the mechanical side of the equation is just fine. Of course, there's always the possibility that the special case arises where the problem doesn't make sense with the logistics. Edited February 23, 2009 by kingman92010 Link to comment Share on other sites More sharing options...
94extreme Posted February 23, 2009 Share Posted February 23, 2009 it wouldn't hurt to check the AT fluid. ecu diagnostic time.. Link to comment Share on other sites More sharing options...
alexrex20 Posted February 24, 2009 Share Posted February 24, 2009 autozone will check it for free.. maybe others too. autozone only checks CELs on '98+ vehicles with an OBDII port. Link to comment Share on other sites More sharing options...
alexrex20 Posted February 24, 2009 Share Posted February 24, 2009 That really sounds like an electronic problem. If it's keeping the gear, that usually means there's sufficient fluid pressure to hold it. If there wasn't enough pressure, it would "fall" out of gear, or not shift into a higher gear at all. On mine when my stock tranny cooler plugged up(mechanical fluid pressure problem, not electronic), it would downshift at retarded times, sometimes dangerously raising the RPMs (downshifting from 3rd to 1st, totally forgetting there was even a 2nd gear in there). This is because the fluid pump works from the rotation of the rear wheels, slowing down the rear wheels would cause it to not keep up with the amount of pressure the tranny needed when the tranny cooler wasn't circulating it properly, in effect causing the gear clutches to disengage and fall out of gear. If it's downshifting properly while slowing down (I forgot what the points were) and upshifting normally (again) on acceleration until overdrive, it sounds like the mechanical side of the equation is just fine. Of course, there's always the possibility that the special case arises where the problem doesn't make sense with the logistics. no. it might be time to flush your ATF, replace the filter and/or replace/clean the solenoids. if your clutch packs are worn, the metal particles will clog the solenoids and cause improper shifting. it wouldn't hurt to drop your trans pan to change fluid, and/or check the magnetic drain plug for excessive metal particles. it's not abnormal to have some, but you'll know if it's too much. Link to comment Share on other sites More sharing options...
94extreme Posted February 24, 2009 Share Posted February 24, 2009 autozone only checks CELs on '98+ vehicles with an OBDII port. i didn't say anything about zone checking the error codes.. his charging system is what we were talking about at that time. Link to comment Share on other sites More sharing options...
alexrex20 Posted February 24, 2009 Share Posted February 24, 2009 i didn't say anything about zone checking the error codes.. his charging system is what we were talking about at that time. my bad. i just skimmed through the posts and wasn't paying attention. Link to comment Share on other sites More sharing options...
Kingman Posted February 24, 2009 Share Posted February 24, 2009 Is there a relay, or a sensor for the E/AT switch? A lot of vehicles have a sensor on the gas pedal to where if you floor it, it makes contact and triggers an automatic kickdown. Link to comment Share on other sites More sharing options...
94extreme Posted February 24, 2009 Share Posted February 24, 2009 i think it's the ecu that does all those adjustments. Link to comment Share on other sites More sharing options...
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