RustyButTrusty Posted December 8, 2009 Share Posted December 8, 2009 Ok, well the automatic transmission on our 88 pathfinder has been rebuilt twice. After driving it on the highway recently, I noticed it shifting from the highest gear back down to the lower gear down (I'm guessing 4th to 3rd), and it does that back and forth more so when going up a moderate grade. Seems like I recall a sensor or something being replaced on it alot earlier in its life for the same problem, but I'm not sure. Has anyone else had this problem and know how to fix it? Appreciate the help! Link to comment Share on other sites More sharing options...
Alkorahil Posted December 8, 2009 Share Posted December 8, 2009 Is the vehicle suffeciently warmed up? The tranny fluid needs to warm up a little before it will funny engage the overdive. Link to comment Share on other sites More sharing options...
RustyButTrusty Posted December 8, 2009 Author Share Posted December 8, 2009 Is the vehicle suffeciently warmed up? The tranny fluid needs to warm up a little before it will funny engage the overdive. I would say so. Last time I drove it was 25 miles one way down the highway at about 65-70 mph, and it did it pretty much the entire trip. Link to comment Share on other sites More sharing options...
MikeV Posted December 8, 2009 Share Posted December 8, 2009 Is it falling in and out of overdrive? (3 speed with overdrive) or between 2nd & 3rd? What sized tire size are you running? Did you install an aftermarket cooler yet? (you should bypass the stock cooler) Link to comment Share on other sites More sharing options...
RustyButTrusty Posted December 9, 2009 Author Share Posted December 9, 2009 Is it falling in and out of overdrive? (3 speed with overdrive) or between 2nd & 3rd? What sized tire size are you running? Did you install an aftermarket cooler yet? (you should bypass the stock cooler) Yes I believe it was falling out of overdrive, and I was running 31x10.50x15's. To tell you the truth, I'm not sure if the stock cooler was replaced or not, I would have to ask my dad to see if they did that when the transmission was rebuilt those times I mentioned. Link to comment Share on other sites More sharing options...
Kingman Posted December 9, 2009 Share Posted December 9, 2009 One of the biggest problems people have with the '88-'95 Pathfinders is the stock cooler clogging up. The materials used in the RE4RO1A transmissions are weaker and produce more debris than the older L3N71B transmissions used in the old 710 Pickups and the '86.5-'87 Pathfinders. Sadly people will replace or rebuild the transmission only to have it fail again because the cooler is still clogged and still starves the transmission of fluid. Treating the symptom, not the problem. Your best bet, whether it be the problem or not, is to install an aftermarket transmission cooler and completely bypass the factory unit. Link to comment Share on other sites More sharing options...
headpeace Posted December 9, 2009 Share Posted December 9, 2009 is your alt or battery on the blink? Link to comment Share on other sites More sharing options...
RustyButTrusty Posted December 9, 2009 Author Share Posted December 9, 2009 Battery is still in good shape, and alternator was replaced within the past 2 or so years. Sounds like replacing the cooler would be a good project once I get the funds up haha, I'll have to see if there is a write-up on here on installing one. Link to comment Share on other sites More sharing options...
SC88Pathy Posted December 9, 2009 Share Posted December 9, 2009 This is the exact same symptoms my transmission had before it lost 4th completely, followed promptly by losing second. Sounds like your transmission shop knew that if they didn't install a cooler you'd be back to have your transmission rebuilt again. Put in a cooler ASAP (like tomorrow), and hope you caught it early enough. Link to comment Share on other sites More sharing options...
RustyButTrusty Posted December 9, 2009 Author Share Posted December 9, 2009 This is the exact same symptoms my transmission had before it lost 4th completely, followed promptly by losing second. Sounds like your transmission shop knew that if they didn't install a cooler you'd be back to have your transmission rebuilt again. Put in a cooler ASAP (like tomorrow), and hope you caught it early enough. Funny you should mention this, I just asked my dad about the transmission cooler. He said the first time he had it rebuilt, the transmission shop put in a cooler, because they said it didn't have one. This shop was also several hours away, my dad had to stop there to have it fixed so he could get it the rest of the way home. He said they probably just put in an aftermarket one, since they were not at dealer. I don't know how reputable this shop was, but we've had several sketchy experiences when its been at different shops. Maybe they were just really pulling his chain. This is probably a dumb question, but can you tell externally if a cooler is installed. I've never messed with autos before just an old 3 speed manual. Link to comment Share on other sites More sharing options...
Simon Posted December 9, 2009 Share Posted December 9, 2009 The stock cooler is in the rad. The problem is, if they ran the new, aftermarket cooler in line with the stock one, the problem hasn't been addressed. Check the lines from the tranny to ensure they go into and out of an aftermarket cooler and DO NOT go into the rad. If they do, get that switched out ASAP. Link to comment Share on other sites More sharing options...
GrimGreg Posted December 9, 2009 Share Posted December 9, 2009 It could be that you are feeling the torque converter lock and unlock on you, it feels like a gear shift when it does. Was the torque converter replaced when the tranny was rebuilt? Link to comment Share on other sites More sharing options...
nismothunder Posted December 9, 2009 Share Posted December 9, 2009 Look on the front of the rad,there should be two coolers,one is the AC condenser and the other is the aftermarket cooler...if theres only one then they didnt install one(unless your pathy doesnt have AC) Link to comment Share on other sites More sharing options...
Precise1 Posted December 9, 2009 Share Posted December 9, 2009 Also, the lines from the tranny are on the passenger side, below the level of the bottom pulley. You can visually trace them if in doubt. I have to play devils advocate; have you checked the tranny fluid level and condition? B Link to comment Share on other sites More sharing options...
RustyButTrusty Posted December 9, 2009 Author Share Posted December 9, 2009 Look on the front of the rad,there should be two coolers,one is the AC condenser and the other is the aftermarket cooler...if theres only one then they didnt install one(unless your pathy doesnt have AC) Ok well I crawled up under the car and verified that there is indeed a cooler installed right in front of the radiator. I traced the hoses connected to it to two metal pipes which then joined up with the transmission I am assuming. I just checked the fluid and it still seemed fine and it wasn't low. Link to comment Share on other sites More sharing options...
nismothunder Posted December 9, 2009 Share Posted December 9, 2009 Are you checking it,by placeing it on level ground and letting it idle until the fluid is moving and then maneully engauging each gear(putting it in each gear spot and then bring it back to park) or are you just opening the hood and pulling the dip stick out,whipping off,replacing and then looking again... This isnt a joke but could you be looking at the oil dip stick by mistake...(tranny onpassger side by fired wall and oil on driver side coming out of the engine) Link to comment Share on other sites More sharing options...
RustyButTrusty Posted December 9, 2009 Author Share Posted December 9, 2009 Are you checking it,by placeing it on level ground and letting it idle until the fluid is moving and then maneully engauging each gear(putting it in each gear spot and then bring it back to park) or are you just opening the hood and pulling the dip stick out,whipping off,replacing and then looking again... This isnt a joke but could you be looking at the oil dip stick by mistake...(tranny onpassger side by fired wall and oil on driver side coming out of the engine) Yes it is on level ground. I checked it cold, should the engine be hot? Yeah it was the trans dipstick (thanks for the suggestion though). Link to comment Share on other sites More sharing options...
nismothunder Posted December 9, 2009 Share Posted December 9, 2009 Yeah,it should be hot,when its cold the fliud is all in the pan,you need to have it at the save part while running,if its at the safe spot when cold then your probly a quirt to a quirt and a half low.If it was me I would change the fluid and dump a bottle of lucas tranny fix in it to see if it helps... Link to comment Share on other sites More sharing options...
Precise1 Posted December 9, 2009 Share Posted December 9, 2009 The 'cold' reading on the dip stick is actually after driving it a few miles and doing the gear selector change like NT outlined and you check the level with the motor running. The 'hot' reading is after driving at freeway speeds for 10 miles or more. I'm trying to top off my level also, and it is kind of a pain in the butt. I seem to get different readings at different times. Not a huge fluctuation, but enough to be irritating. B Link to comment Share on other sites More sharing options...
Dowser Posted December 10, 2009 Share Posted December 10, 2009 Battery is still in good shape, and alternator was replaced within the past 2 or so years. Sounds like replacing the cooler would be a good project once I get the funds up haha, I'll have to see if there is a write-up on here on installing one. I just happen to finish reading these so here ya go. both are very informative. Tranny Cooler. Precise's Tranny Guage. Hope that helps. Link to comment Share on other sites More sharing options...
RustyButTrusty Posted December 11, 2009 Author Share Posted December 11, 2009 Ok well thanks guys for all the help, I really appreciate it. Currently the pathfinder isn't registered so I can't drive it too far. I'll check the fluid again (the correct way) and proceed from there. Thanks again! Link to comment Share on other sites More sharing options...
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