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Transmission Issues


ryjaytay38
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Hey guys,

About a year ago I had a radiator go, replaced it only to find the motor was leaking. I came on here and was informed about the water outlet tube on the back of the motor and the gaskets having a habit of giving out. Found a 3-4 inch hose going from the block to the rear thermostat had blown out and thought I was in the clear after I replaced it. It leaked again and I knew it was the gaskets. Tried getting it done from the top and it leaked again. I thought I will do the transmission drop which I was trying to avoid, but I went ahead with it. I disconnected everything in order to drop it, including the metal cooling lines and losing quite a bit of trans fluid in the process. Right before I pulled the last two bell housing bolts, I thought, I know I can do this without dropping this thing and didn't pull the last few bolts. I ended up pulling the plenum and manifolds again, put rtv on the gaskets this time, and got it tightened down. I put everything back together fired it up and up to temp and what do you know...NO LEAKING!!! Time to drive it.

I had read that if you haven't changed your trans fluid in a long time, and I hadn't, that you shouldn't change it. Mine looked more like oil and no reddish color to speak of. However, I did have to add quite a bit that I had lost. As soon as I put it in reverse, it engaged and backed out of the driveway. I thought ok, good first step. Put it in drive and it engaged--now I'm really happy...until I pushed the accelerator. It's starting in 2nd gear. I've gone through all the gears and it will shift to 3rd and 4th smoothly, but it won't go to first. Or should I say, I don't know how to get it to go to first. 

Is there any adjustment that I can make? Any tricks that anyone can help me with? There is no hesitation, no clicking, no nothing that would cause alarm, it just does not want to go to first.

Any ideas or knowledge anyone can lend would be most appreciated!!

Thanks in advance!!

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I haven't had a problem from changing old trans fluid. It was one of the first things I did when I got mine in hopes of extending the life of a high-mileage transmission. Brown trash out, red trash in. 20k later it's no worse than it was. I suspect the "new fluid kills it" story comes from people changing the fluid as a last-ditch attempt to save a trans that is already slipping, where the thin gritty fluid was the only thing making the clutches grab at all. A few years ago I changed the trans fluid on an S10 where the fluid was black and smelled like a wet ashtray, and that thing's still going, much to my amazement. 

 

Rather than fluid quality, I would look at the quantity. Trans fluid levels can be PITA to set correctly, and I've read overfilling can cause the transmission to act strangely. The dipstick's meant to be read with the engine and trans warmed up. I set mine cold, warmed it up, and had to drain some back out. I would also double-check any electrical connectors you disturbed when you thought you were dropping the trans, though if something wasn't plugged in I'd expect trouble codes.

IIRC the WD21 manual tells you what temperature to check the fluid level at, which would be nice if they gave you any idea of how to check the fluid temp. I haven't checked the '01 manual but I wouldn't be surprised if you could check that through live data on an OBDII scanner. 

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Thanks for the reply! I will fire it up again tonight and see if I overfilled. I started by doing what you had done-measure cold. Then I remembered that it had to be hot and I'm not 100% on what the dipstick was reading because I was so happy that it was running! Now that I've come back down to earth and had the day to dwell on it, I'll see what i can come up with. Thanks again! 

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One other thing Slartibartfast, which metal tube from the transmission goes to which side? I've looked all over but get different answers. I know one side of the radiator gets the "hot" which would be intake but I'm not sure which side is output cool

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If you're asking which hard line is supply vs return for the cooler, looks like this guy found the answer. Fluid leaves the trans on the driver's side, returns on the passenger's side.

 

The procedure to set the fluid level (with target temps and all) is in the MA section of the service manual BTW. Good luck!

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  • 2 weeks later...

I finally got to my Pathfinder. Slartibartfast suggested that I may have overfilled the transmission. I drained almost 2 quarts out and now it takes off normally, but I'm getting the old P0300 code-multiple cylinder misfire, by itself.  I've heard that the P0300 code by itself is usually something unrelated to the ignition. That kind of opens it up to a huge number of possibilities. Does anyone have any suggestions of where to start? Should I go to coils and spark plugs, injectors etc to rule that out?

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Halfway there!

 

I don't remember what code it threw, if any, but IIRC my dad's '01 had a random intermittent misfire that the dealer said was probably a coil pack. They couldn't track down which one was the problem and wanted to do them all. A set of coil packs ain't cheap, so I would first look for any obvious vac leaks, gunk on the MAF, maybe check the color and condition of the spark plugs to see if you've got an overall mixture issue or an obvious single-cylinder fault (or a bunch of oil in the plug wells). Have a look at the coil packs while they're out, look for evidence of arcing.

Do you feel the misfire under certain conditions?

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Slartibartfast, I changed it all. New coil packs and new plugs. Code is gone but still running rough. I'm thinking it might be old gas but the concern now is transmission again. I drove about 10 miles and it runs ok, not chugging or anything but it doesn't want to shift properly. I've checked over and over on the trans fluid level and it's right on the mark. When I take off, it is now starting in 1st at least since I drained a bunch out, but it shifts to 2nd pretty hard and then it seems to just trickle down throught the gears. Next thing you know, it's in 5th doing 25 but it won't downshift unless I come to a stop, put it in park quickly and back to drive, the process starts again. Is there anyway it's going through a " break in" period since there's quite a bit of new fluid in there? Should I just keep driving and see if it comes out of it's funk? I wish I knew a little about trannys, but I don't have a clue. The most I've done was to my 99 Trooper when I put a torque converter in  and changed the filter in the pan. I'm not even sure what tranny this is. My Trooper is a 4L30 but I've looked online and don't see @!*% for the 01 Pathfinder. 

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Well, that sucks. I wouldn't expect a break-in or relearn or any of that--though you might try resetting the computer on the off chance the computer got confused when the fluid was overfilled. I remember punching some kind of Konami code into my dad's '03 to reset the engine computer (following instructions in the service manual), but just unhooking the battery for a while would probably do the same thing. Long shot, though.

 

Running it when it's not shifting right might cause damage depending on what the problem is. 

The transmission is an RE4R01A. The AT section of the service manual has a bunch of troubleshooting in it, though naturally they assume you've got Consult. They were also used in Skylines, so there is some 3rd party info out there as well. (Serious rabbit hole advisory on that link, BTW.)

Short-shifting makes me think it may be getting bad info from the engine computer. Maybe the same bad info is why the engine is running poorly. If you've got a code scanner that will show live data, I would take a look at the data from the throttle position sensor. See if the % jumps around when you open/close the throttle slowly.

IIRC there's a sensor at the top of the bellhousing that reads engine speed off the flywheel teeth, or something like that? I only remember it as something that's on the Xterra trans that you don't use if swapping it into a WD21. But that's something you could've unhooked when prepping to drop the trans, then missed when buttoning it up (or bumped the sensor out of position or something). Given that this issue started when you messed with the transmission, I would check that you got everything buttoned back up properly. (That goes for any sensors/wiring you moved to pull the plenum, too.)

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I will go back under and see if there's something I disconnected. It kind of sucks that I have this love for this truck! I could drive something thats nicer looking, better on gas, has more power, but I can't go take it to salvage. This stubborn streak in me says I can fix it. One way or another, I'll get it rolling. 

My reader doesn't do real time. It's old and sucks and I need a new one. I think I'm going to get a new one next week. A friend will let me borrow his. When I connect and get into throttle position sensor, just accelerate/decellerate and see if the % fluctuates? What is that going to tell me?

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Doesn't even have to be running. Key on, engine off. Press the pedal slowly. The number should rise as the pedal goes down, then fall as you let off. If the number bounces around with little regard to where the pedal is, or drops/spikes randomly, the sensor is borked. Think of it like the volume knob on a stereo. If it's good, the volume goes up and down when you turn the knob. If it's bad, it pops and crackles and drops out if you stop in the wrong spot. 

 

Don't condemn the sensor if it doesn't go all the way to 100%. I've seen that on other vehicles and it wasn't causing problems, so I left it alone. 

 

Unless you damaged the sensor or its wiring while you had the intake apart, I doubt this'll end up being the issue, but (if you have the tool) it's an easy thing to try.

And yeah, I hear you on "I won't let this wore-out POS die on me now." I've been there with mine. Actually I'm kinda still there. Good luck!

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Having gone through some transmission issues recently, my thoughts go to the shift solenoids. Hard to really put all my chips on any particular path I might offer, but if you got a new radiator because the tranny cooler leaked, and or milkshake or worse was found in your transmission, if perhaps you don't know how long it had been running that way when you started having issues,(maybe you were on some logging road when it first gave out). I'm going to suggest you might need to have your transmission looked at.

You can test your solenoids, and a host of other things which will cause you to learn a bunch about the true state of your aging Pathfinder and vehicle maintenance and diagnostics along they way.
You could save time by taking it to a professional. If the tranny is the main concern, or perhaps tranny related, having them diagnose the transmission puts the job closer to a rebuild financially and physically so you might as well save/rebuild/replace. But of course you should have the evidence to support it. It's always tough to end up at such extremes, but if it needs it, it needs it and deserves concern.

I thought it the best of both worlds from my recent experiences. Professionally rebuilt tranny/learned a thing or 22 about my current dd. (fsm also an "interesting" read. haha.)

It's great when/if you can get on top of it, but mileage will vary.



Sent from my SM-N960U1 using Tapatalk

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  • 3 months later...

Hey guys! Long time no chat. I have some interesting news. I was having all of these mysterious "transmission problems". I got so pissed that I swore it's going to the 'Ol junkyard. I left it alone for the last few months without the heart to put it down. I kept thinking about a friend who's my shop tech at work who said if the engine isn't running right, the tranny isn't going to either. I let that rattle around in the melon for a few and went out to start looking at the engine. I started it and just started touching wires, connections, pushing things, pulling etc. I grabbed the big harness across the front of the motor and the whole sound changed. I started looking at critical wires that were connected to it. I feel pretty foolish even writing this,  but it shows you that a lot of the problems are right in front of you and look for the simple stuff first. Long story shorter, 4 out of 6 ignition coils wires were cracked. I went on Amazon and ordered pigtails for all 6, put them on and the truck is back!!! Running as strong as I've ever felt it. 

It's crazy to me how this thing would just shift down to 5th going down the road at 20mph but nothing wrong with the tranny. I guess it does make sense since it was running on 2 cylinders!!

Thank you all for the help and efforts to get this beast back and rolling again. I appreciate the time you took to post to help me out. Next project is paint!!!

Thanks again!!

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2 hours ago, ryjaytay38 said:

Hey guys! Long time no chat. I have some interesting news. I was having all of these mysterious "transmission problems". I got so pissed that I swore it's going to the 'Ol junkyard. I left it alone for the last few months without the heart to put it down. I kept thinking about a friend who's my shop tech at work who said if the engine isn't running right, the tranny isn't going to either. I let that rattle around in the melon for a few and went out to start looking at the engine. I started it and just started touching wires, connections, pushing things, pulling etc. I grabbed the big harness across the front of the motor and the whole sound changed. I started looking at critical wires that were connected to it. I feel pretty foolish even writing this,  but it shows you that a lot of the problems are right in front of you and look for the simple stuff first. Long story shorter, 4 out of 6 ignition coils wires were cracked. I went on Amazon and ordered pigtails for all 6, put them on and the truck is back!!! Running as strong as I've ever felt it. 

It's crazy to me how this thing would just shift down to 5th going down the road at 20mph but nothing wrong with the tranny. I guess it does make sense since it was running on 2 cylinders!!

Thank you all for the help and efforts to get this beast back and rolling again. I appreciate the time you took to post to help me out. Next project is paint!!!

Thanks again!!

@ryjaytay38, I always say "when in doubt look again" that's often when we find the root cause of some of these issues. Sometimes walking away and taking a break helps too as you've just proven. I'm glad you were finally able to figure it out!

 

Chris.

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